Tunable notch filter and contour tuning circuit

ABSTRACT

Aspects of this disclosure relate tuning an impedance presented to a common port of a multi-throw switch and a tunable notch filter coupled to the common port. The impedance presented to the common port can be tuned based on an impedance associated with a throw of the multi-throw switch that is activated. According to embodiments of this disclosure, a shunt inductor in parallel with a tunable capacitance circuit can tune the impedance presented to the common port of the multi-throw switch. In certain embodiments, the tunable notch filter includes a series LC circuit in parallel with a tunable impedance circuit.

CROSS REFERENCE TO PRIORITY APPLICATIONS

This application claims the benefit of priority of U.S. ProvisionalPatent Application No. 62/211,557, filed Aug. 28, 2015 and titled“TUNABLE NOTCH FILTER,” the disclosure of which is hereby incorporatedby reference in its entirety herein. This application also claims thebenefit of priority of U.S. Provisional Patent Application No.62/213,546, filed Sep. 2, 2015 and titled “TUNABLE ANTENNA FILTER,” thedisclosure of which is hereby incorporated by reference in its entiretyherein.

BACKGROUND

Technical Field

Embodiments of this disclosure relate to electronic systems and, inparticular, to radio frequency systems.

Description of Related Technology

A radio frequency (RF) telecommunications system can transmit and/orreceive RF signals that meet demands of high density, high speedoperation. Wireless communication devices, such as mobile phones, caninclude RF systems and transmit and receive signals in a cellularnetwork. RF systems can include RF circuitry such as filters, RFamplifiers, and RF switches arranged to process RF signals.

RF systems can process signals associated with multiple frequency bands.To support the proliferation of frequency bands, there can be a numberof different signal paths associated with different frequency bands inan RF system. Such RF systems can include RF circuitry between anantenna and a transceiver. The RF circuitry can include filters, RFamplifiers, and RF switches arranged to process signals associated withvarious frequency bands. The RF circuitry can be arranged such that RFsignals associated with different frequency bands are processed in amanner that is tailored to a specific frequency band. For instance, RFsignals within different frequency bands can be filtered in a mannerthat is tailored so as to reject frequencies outside of their respectivefrequency bands. Alternatively or additionally, the RF circuitry can bearranged such that RF signals associated with different signal paths areprocessed in a manner that is tailored to a specific signal path.

Carrier aggregation in the cellular networks has been a driver forsignificant improvement in transmit harmonic levels such that atransmitter of a mobile phone may not significantly regrade receiversignals. It can be desirable to implement filtering withoutsignificantly degrading insertion loss to prevent the transmitter fromdegrading receiver signals.

SUMMARY OF CERTAIN INVENTIVE ASPECTS

The innovations described in the claims each have several aspects, nosingle one of which is solely responsible for its desirable attributes.Without limiting the scope of the claims, some prominent features ofthis disclosure will now be briefly described.

One aspect of this disclosure is a radio frequency circuit that includesan antenna switch having multiple throws, a tunable circuit, and atunable notch filter. The tunable circuit is configured to adjust aneffective shunt impedance in a signal path from the antenna switch to anantenna port in association with a state of the antenna switch changing.The tunable notch filter is coupled in series between the antenna switchand the antenna port. The tunable notch filter is configured to filter aradio frequency signal propagating between the antenna switch and theantenna port.

The tunable notch filter can be tuned so as to have a frequency responsewith a notch at a second harmonic frequency of the radio frequencysignal. The tunable notch filter can include a series circuit inparallel with a tunable capacitance circuit. The tunable capacitancecircuit and the antenna switch can be integrated on a commonsemiconductor die. The series LC circuit can be inductive at frequenciesabove a resonant frequency of the series LC circuit so as to create aparallel resonance with the tunable capacitance circuit. The radiofrequency can further include a control circuit configured to controlthe tunable capacitance circuit of the tunable notch filter such that aneffective capacitance in parallel with the series LC circuit correspondsto a frequency of the radio frequency signal.

The tunable circuit can include a shunt inductor in parallel with atunable capacitance circuit. The radio frequency circuit can furtherinclude a control circuit configured to control the tunable circuit soas to provide a first effective shunt impedance when a first throw ofthe antenna switch is active and to provide a second effective impedancewhen a second throw of the antenna switch is active.

The radio frequency circuit can further include a control circuitconfigured to set a state of the tunable circuit based on an impedanceassociated with a trace arranged to route from a duplexer to a throw ofthe antenna switch that is activated. Alternatively or additionally, theradio frequency circuit can include a trim and control circuit includingnon-volatile memory storing trim data. The trim and control circuitconfigured to set a state of the tunable notch filter based at leastpartly on the trim data. The antenna switch can have at least 8 throws,for example.

Another aspect of this disclosure is packaged module that includes amulti-throw switch, a tunable circuit, and a tunable notch filter. Themulti-throw switch includes input/output ports and a common port. Themulti-throw switch is configured to electrically connect a selected oneof the input/output ports to the common port. The tunable circuit isconfigured to adjust an effective shunt impedance coupled to the commonport in association with a state of the antenna switch changing. Thetunable notch filter is coupled in series in a radio frequency signalpath associated with the common port. The multi-throw switch, thetunable circuit, and the tunable notch filter are included within acommon package.

The tunable circuit can include a shunt inductor in parallel with atunable capacitance circuit. The tunable notch filter can include aseries LC circuit in parallel with a tunable capacitance circuit. Thetunable notch filter can provide rejection at a second harmonic of aradio frequency signal propagating between the common port and thetunable notch filter.

The packaged module can further include a trim and control circuitincluding memory arranged to store trim data. The trim and controlcircuit can set a state of the tunable notch filter based on the trimdata.

The packaged module can further include a power amplifier includedwithin the common package.

Another aspect of this disclosure is a wireless communication devicethat includes an antenna configured to receive a radio frequency signal,an antenna switch, a tunable circuit, and a tunable notch filter. Theantenna switch is configured to electrically couple a first radiofrequency signal path to the antenna in a first state and toelectrically couple a second radio frequency signal path to the antennain a second state. The tunable circuit is configured to adjust aneffective shunt impedance in a signal path from the antenna switch tothe antenna in association with a state of the antenna switch changing.The tunable notch filter is coupled in series between the antenna switchand the antenna.

The wires communication device can be a mobile phone, such as a smartphone. The tunable circuit can be configurable into at least 8 states.

Another aspect of this disclosure is a radio frequency system thatincludes a multi-throw switch configured to provide a radio frequencysignal, a shunt inductor, and a tunable capacitance circuit. Themulti-throw switch has at least a first throw, a second throw, and acommon port. The shunt inductor and the tunable capacitance circuit arecoupled to the common port. The tunable capacitance circuit isconfigured to provide a first effective capacitance in parallel with theshunt inductor when the first throw is active and to provide a secondeffective capacitance in parallel with the shunt inductor when thesecond throw is active.

The radio frequency system can be arranged such that the radio frequencysignal propagates between the common port of the multi-throw switch andan antenna port. The radio frequency system can further include atunable notch filter electrically coupled between the common port andthe antenna port. The tunable notch filter can include a series LCcircuit in parallel with a second tunable capacitance circuit. The radiofrequency system can further include a harmonic filter in series withthe tunable notch filter.

The radio frequency system can further include a control circuitconfigured to set a state of the tunable capacitance circuit. Thecontrol circuit can set the state of the tunable capacitance circuitbased at least partly on a characteristic of a throw of the multi-throwswitch that is activated. The characteristic can be an impedanceassociated with the throw that is activated.

The multi-throw switch and the tunable capacitance circuit areintegrated on a common semiconductor die. The multi-throw switch caninclude at least 8 throws. The first throw and the second throw of themulti-throw switch can be associated with different frequency bands. Thetunable capacitance circuit can include series circuits each including acapacitor in series with a switch, and each of the series circuits arein parallel with the shunt inductor.

Another aspect of this disclosure is a packaged module that includes amulti-throw switch, an antenna port, a shunt inductor coupled in asignal path between the multi-throw switch and the antenna port, and atunable capacitance circuit configured to provide different effectivecapacitances in parallel with the shunt inductor when different throwsof the multi-throw switch are active. The tunable capacitance circuit,the shunt inductor, and the multi-throw switch are enclosed within acommon package.

The packaged module can further include a control circuit configured toset a state of the tunable capacitance circuit to match an impedanceassociated with a throw of the multi-throw switch that is activated. Thepackaged module can further include a tunable notch filter electricallycoupled between the multi-throw switch and the antenna port. Thepackaged module can further include a power amplifier enclosed withinthe common package. Different throws of the multi-throw switch can beassociated with different respective frequency bands.

Another aspect of this disclosure is a method of tuning an impedance ata common port of a multi-throw switch. The method includes adjusting aneffective capacitance in parallel with a shunt inductor coupled to thecommon port of the multi-throw switch in association with a state of themulti-throw switch changing.

Adjusting the effective impedance can include tuning a switch on tocouple capacitor in parallel with the shunt inductor. The shunt inductorand the tunable capacitor can be coupled to a node is a signal pathbetween the common port and an antenna port.

Another aspect of this disclosure is a wireless communication devicethat includes an antenna configured to transmit a radio frequencysignal, an antenna switch configured to electrically couple a firstradio frequency signal path to the antenna in a first state and toelectrically couple a second radio frequency signal path to the antennain a second state, and a tunable capacitance circuit in parallel with ashunt inductor coupled between the antenna switch and the antenna. Thetunable capacitance circuit is configured to adjust an effectivecapacitance in parallel with the shunt inductor in association with astate of the antenna switch changing.

The wireless communication device can be a mobile phone. The tunablecapacitance circuit can be configurable into at least 8 states.

Another aspect of this disclosure is a radio frequency system thatincludes a multi-throw switch configured to selectively electricallyconnect a radio frequency (RF) signal path to a common node of themulti-throw switch and a tunable filter electrically coupled between thecommon node and a voltage reference, such as a ground potential. Thetunable filter is coupled to a node is a signal path between the commonnode and an antenna port. The tunable filter includes a tunableimpedance circuit.

The tunable impedance circuit can be a tunable capacitance circuit. Thetunable impedance circuit can be in parallel with a shunt inductor.

The radio frequency system can include a control circuit configured toset a state of the tunable impedance circuit based at least partly onwhich throw of the multi-throw switch is activated. The control circuitcan set the state of the tunable impedance circuit based at least partlyon a characteristic of an input of a throw of the multi-throw switchthat is activated. The characteristic can be an impedance associatedwith the input of the throw that is activated.

The radio frequency system can include a tunable notch filterelectrically coupled between the tunable filter and the antenna port.Tunable notch filter can includes a series LC circuit in parallel with atunable capacitance circuit. The radio frequency system can include aharmonic filter electrically coupled between the tunable filter and thetunable notch filter. The harmonic filter can be an elliptical filter.

The tunable filter and the multi-throw switch can be included in anantenna switch module. In the antenna switch module, a package canenclose the multi-throw switch and the tunable filter. The packaged canalso include a power amplifier. The multi-throw switch and at least aportion of the tunable filter can be integrated on a common die.

The common node of the multi-throw switch can be electrically connectedto multiple throws of the multi-throw switch and each of the multiplethrows can be electrically connected to a different RF signal path. Thecommon node of the multi-throw switch can be electrically connected toeach throw of the multi-throw switch. Different throws of themulti-throw switch can be associated with different respective frequencybands. Each throw of the multi-throw switch can include a shunt arm anda switch arm. The multi-throw switch can include at least 8 throws. Themulti-throw switch can include a single pole.

Another aspect of this disclosure is a radio frequency system thatincludes a multi-throw switch, an antenna port, and a tunable circuitcoupled to anode between the multi-throw switch and the antenna port.The tunable circuit includes a shunt inductor in parallel with a tunablecapacitance circuit.

The radio frequency system can include a control circuit configured toset a state of the tunable capacitance circuit based at least partly onwhich throw of the multi-throw switch is activated. The control circuitcan set the state of the tunable capacitance circuit based at leastpartly on a characteristic of an input of a throw of the multi-throwswitch that is activated. The characteristic can be an impedanceassociated with the input of the throw that is activated.

The radio frequency system can include a tunable notch filterelectrically coupled between the tunable circuit and the antenna port.The tunable notch filter can include a series LC circuit in parallelwith a tunable capacitance circuit. The radio frequency system caninclude a harmonic filter electrically coupled between the tunablecircuit and the tunable notch filter. The harmonic filter can be anelliptical filter.

An antenna switch module can include the multi-throw switch and thetunable filter within a common package. The multi-throw switch and atleast a portion of the tunable circuit can be integrated on a commondie, such as a semiconductor-on-insulator die. A power amplifier can beenclosed within the common package.

Different throws of the multi-throw switch can be associated withdifferent respective frequency bands. Each throw of the multi-throwswitch can include a shunt arm and a switch arm. The multi-throw switchcan include at least 8 throws. The multi-throw switch can include asingle pole.

Another aspect of this disclosure is a radio frequency system thatincludes an antenna switch having multiple throws, a low pass filter ina signal path between the antenna switch and an antenna port, and atunable notch filter in the signal path between the antenna switch andthe antenna port. The tunable notch filter includes a series LC circuitin parallel with a tunable impedance circuit. The series LC circuit iscoupled in series between the antenna switch and the antenna port.

The tunable notch filter can provide a notch at a second harmonicfrequency of a radio frequency signal propagating between the antennaswitch and the antenna port. A radio frequency signal propagatingbetween the antenna switch and the antenna port can have a power of atleast 15 decibel-milliwatts. The series LC circuit can be inductive atfrequencies above a resonant frequency of the series LC circuit. Theseries LC circuit can create a parallel resonance with the tunableimpedance circuit to provide a notch in a frequency response of thetunable notch filter. The series LC circuit can effectively short thetunable impedance element at a frequency of a radio frequency signalpropagating between the antenna switch and the antenna port.

The radio frequency system can further include a control circuitconfigured to control the tunable impedance circuit such that theimpedance in parallel with the series LC circuit corresponds to afrequency of a radio frequency signal propagating between the antennaswitch and the antenna port. The radio frequency system can include acontrol circuit configured to control the tunable impedance circuit soas to provide an impedance in parallel with the series LC circuitcorresponding to a throw of the antenna switch that is activated.

The tunable impedance circuit can include a tunable capacitance circuit.The tunable capacitance circuit can include switches implemented on asilicon-on-insulator die on which the antenna switch is implemented. Thetunable capacitance circuit can include a plurality of capacitors eachin series with a respective switch.

The low pass filter can be an elliptical filter. The low pass filter canprovide a short at a frequency of about 5 GHz. The low pass filter canprovide a frequency trap at a third harmonic of a radio frequency signalbeing provided from the antenna switch to the antenna port.

The antenna switch can have at least 8 throws, for example. The antennaswitch can have at least two poles in certain implementations.

The radio frequency system can further include a trim and controlcircuit including non-volatile memory storing trim data. The trim andcontrol circuit can set a state of the tunable impedance circuit basedat least partly on the trim data. According to certain implementations,non-volatile memory of the trim and control circuit includes fuseelements.

Another aspect of this disclosure is a packaged module that includes amulti-throw switch and a tunable notch filter. The multi-throw switchincludes input/output ports and a common port. The multi-throw switch isconfigured to electrically connect a selected one of the input/outputports to the common port. The tunable notch filter includes a series LCcircuit in parallel with a tunable impedance circuit. The tunable notchfilter is coupled in series in a radio frequency signal path associatedwith the common port. The multi-throw switch and the tunable notchfilter are enclosed within a common package.

The packaged module can further include a low pass filter in series withthe tunable notch filter between the multi-throw switch and an antennaport. The tunable notch filter can provide rejection at a secondharmonic of a carrier. The packaged module can further include a poweramplifier included within the common package in some implementations.The packaged module can be a component for a mobile device.

The packaged module can further include a trim and control circuitincluding memory arranged to store trim data. The trim and controlcircuit can set a state of the tunable filter based at least partly onthe trim data. The trim and control circuit can set the state of thetunable capacitance circuit based at least partly on adding trim dataassociated with a process trim state and data associated with notchtuning states. The trim data can represent a process variationassociated with a fixed portion of the tunable notch filter.

Another aspect of this disclosure is a wireless communication devicethat includes an antenna, an antenna switch, and a tunable notch filter.The antenna is configured to transmit a radio frequency signal. Theantenna switch is configured to electrically couple a first radiofrequency signal path to the antenna in a first state and toelectrically couple a second radio frequency signal path to the antennain a second state. The tunable notch filter is coupled in series betweenthe antenna switch and the antenna. The tunable notch filter includes aseries LC circuit in parallel with a tunable impedance circuit.

The radio frequency signal can be carrier aggregated signal. Thewireless communication device can be a smart phone. The radio frequencysignal transmitted by the antenna can be filtered by the tunable notchfilter and a low pass filter in series with the tunable notch filter.

Another aspect of this disclosure is a method of tuning a tunable notchfilter that includes a series LC circuit in parallel with a tunablecapacitance circuit. The method includes providing tuning data to thetunable capacitance to set a notch in a frequency response of thetunable filter at a first frequency. The method further includesadjusting the tuning data provided to the tunable capacitance circuit tomove the notch in the frequency response of the tunable filter to asecond frequency.

The method can include providing a radio frequency signal to the tunablenotch filter by way of a multi-throw switch. The tunable notch filtercan be in a signal path between the multi-throw switch and an antenna.In some other implementations, the tunable notch filter can be coupledbetween an output of a power amplifier and a common port of amulti-throw switch.

The tunable notch filter can suppress a second harmonic of a radiofrequency signal being filtered by the tunable notch filter. Amulti-throw switch can provide radio frequency signals in differentfrequency bands to the tunable notch filter. The first frequency cancorrespond to a second harmonic of a first radio frequency signalprovided by the multi-throw switch and the second frequency cancorrespond to a second harmonic of a second radio frequency signalprovided by the multi-throw switch.

The method can include adding trim data representative of a processvariation of the series LC circuit with notch tuning data to generatethe tuning data. The method can include accessing the trim data fromnon-volatile memory.

Another aspect of this disclosure is a packaged module that includes atrim circuit including memory to store trim data, a tunable filter in aradio frequency signal path, and a control circuit configured to set astate of the tunable filter based on the trim data and data indicativeof a desired characteristic of the tunable filter. The trim circuit, thetunable filter, and the control circuit are included within a commonpackage.

The radio frequency signal path can be between an antenna switch moduleand an antenna port.

The tunable filter can include a series LC circuit in parallel with atunable capacitance circuit. The trim data can represent a processvariation associated with the series LC circuit. The tunable filter canbe a tunable notch filter and the desired characteristic of the tunablefilter is a notch. The tunable notch filter can provide second harmonicrejection of a carrier.

The trim data can represent a process variation associated with a fixedportion of the tunable filter. The memory of the trim circuit caninclude non-volatile memory. For instance, the memory of the trimcircuit can includes fuse elements.

For purposes of summarizing the disclosure, certain aspects, advantagesand novel features of the innovations have been described herein. It isto be understood that not necessarily all such advantages may beachieved in accordance with any particular embodiment. Thus, theinnovations may be embodied or carried out in a manner that achieves oroptimizes one advantage or group of advantages as taught herein withoutnecessarily achieving other advantages as may be taught or suggestedherein.

For purposes of summarizing the disclosure, certain aspects, advantagesand novel features of the innovations have been described herein. It isto be understood that not necessarily all such advantages may beachieved in accordance with any particular embodiment. Thus, theinnovations may be embodied or carried out in a manner that achieves oroptimizes one advantage or group of advantages as taught herein withoutnecessarily achieving other advantages as may be taught or suggestedherein.

The present disclosure relates to U.S. patent application Ser. No.15/247,742, titled “CONTOUR TUNING CIRCUIT,” filed on even dateherewith, the entire disclosure of which is hereby incorporated byreference herein. The present disclosure relates to U.S. patentapplication Ser. No. 15/247,616, titled “TUNABLE NOTCH FILTER,” filed oneven date herewith, the entire disclosure of which is herebyincorporated by reference herein.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of this disclosure will now be described, by way ofnon-limiting example, with reference to the accompanying drawings.

FIG. 1A is a schematic diagram of a radio frequency system including asignal path to an antenna according to an embodiment.

FIG. 1B is a schematic diagram of an illustrative tunable capacitancecircuit according to an embodiment.

FIG. 2 is a schematic diagram of another radio frequency systemincluding a signal path to a low noise amplifier according to anembodiment.

FIG. 3 is a schematic diagram of a radio frequency system with a contourtuning circuit according to another embodiment.

FIG. 4A is a Smith chart showing target duplexer antenna impedancesaccording to an embodiment.

FIG. 4B illustrates a portion of a module with a trace on a packagingsubstrate.

FIG. 5 is a schematic diagram of a radio frequency system with a contourtuning circuit according to an embodiment.

FIG. 6 is a schematic diagram of a model of the radio frequency systemof FIG. 5 during operation.

FIG. 7 is a graph that illustrates relationships of insertion loss overfrequency for signal paths between a common port of an antenna switchand an antenna.

FIG. 8 is a Smith chart of transmit contour tune states of a tunablecapacitance circuit according to an embodiment.

FIG. 9 is a schematic diagram of a model of a signal path between aduplexer and an antenna in accordance with an embodiment.

FIG. 10 is a schematic diagram of a model of a signal path between aduplexer and an antenna in accordance with another embodiment.

FIG. 11A is a schematic diagram of a radio frequency front end accordingto an embodiment.

FIG. 11B is a schematic diagram of a radio frequency front end accordingto another embodiment.

FIG. 12 is a schematic block diagram showing more details of antennafilters according to an embodiment.

FIG. 13 is a schematic block diagram of a module according to anembodiment.

FIG. 14 is a schematic block diagram of a module according to anotherembodiment.

FIG. 15 is a schematic diagram of a packaged module according to anembodiment.

FIG. 16 is a schematic diagram of a radio frequency system that includesa tunable notch filter according to an embodiment.

FIG. 17A is a schematic diagram of a tunable notch filter according toan embodiment.

FIG. 17B is a graph showing a relationship of impedance versus frequencyfor the notch filter of FIG. 17A.

FIG. 17C is schematic diagram illustrating that a series LC circuit ofthe notch filter of FIG. 17A is inductive at a relatively highfrequency.

FIG. 17D is a graph illustrating a relationship of impedance versusfrequency associated with the tunable notch filter of FIG. 17C.

FIG. 17E is a schematic diagram of a tunable notch filter according toanother embodiment.

FIG. 18A is a schematic diagram of antenna filters including a tunableantenna filter according to an embodiment.

FIG. 18B is a schematic diagram of antenna filters including a tunableantenna filter according to another embodiment.

FIG. 19 is a graph showing plots of insertion loss versus frequency fora tunable antenna filter according to an embodiment.

FIG. 20 is a graph showing plots of filter response versus frequency fora tunable antenna filter according to an embodiment.

FIG. 21 is a graph showing plots of insertion loss versus frequency foran antenna switch and a tunable antenna filter according to anembodiment.

FIG. 22 is a schematic diagram of a radio frequency system that includesa tunable notch filter and a trim and control circuit according to anembodiment.

FIG. 23 is a schematic diagram of a trim and control circuit accordingto an embodiment.

FIG. 24 is a schematic diagram of a radio frequency system with atunable notch filter according to an embodiment.

FIG. 25 is a schematic diagram of a radio frequency system with atunable notch filter according to another embodiment.

FIG. 26A is a schematic diagram of a packaged module that includes atunable notch filter according to an embodiment.

FIG. 26B is a schematic diagram of a packaged module that includes atunable notch filter according to an embodiment.

FIG. 27 is a schematic diagram of an RF system according to anembodiment.

FIG. 28A is a schematic block diagram showing more details of antennafilters according to an embodiment.

FIG. 28B is a schematic block diagram showing more details of antennafilters according to another embodiment.

FIG. 29 is a schematic block diagram of a module according to anembodiment.

FIG. 30 is a schematic diagram of a radio frequency system that includesa tunable notch filter and a contour tuning circuit according to anembodiment.

FIG. 31 is a schematic diagram of a radio frequency system that includesa tunable notch filter and a contour tuning circuit according to anotherembodiment.

FIG. 32 is a schematic diagram of a radio frequency system that includesa tunable notch filter and a contour tuning circuit according to anotherembodiment.

FIG. 33 is a schematic diagram of a packaged module that includes atunable notch filter and a contour tuning circuit according to anembodiment.

FIG. 34 is a schematic diagram of a packaged module that includes atunable notch filter and a contour tuning circuit according to anotherembodiment.

FIG. 35 is a schematic block diagram of illustrative wirelesscommunication device that includes a tuning circuit and/or a tunablenotch filter in accordance with one or more embodiments.

DETAILED DESCRIPTION OF CERTAIN EMBODIMENTS

The following detailed description of certain embodiments presentsvarious descriptions of specific embodiments. However, the innovationsdescribed herein can be embodied in a multitude of different ways, forexample, as defined and covered by the claims. In this description,reference is made to the drawings where like reference numerals and/orsymbols can indicate identical or functionally similar elements. It willbe understood that elements illustrated in the figures are notnecessarily drawn to scale. Moreover, it will be understood that certainembodiments can include more elements than illustrated in a drawingand/or a subset of the elements illustrated in a drawing. Further, someembodiments can incorporate any suitable combination of features fromtwo or more drawings. The headings provided herein are for convenienceonly and do not necessarily affect the scope or meaning of the claims.

Contour Tuning Circuit

Current cellular phones and other mobile devices may incorporate anumber of operating bands to support the proliferation of frequencybands over the world. Each separate frequency band can involveparticular filtering to reject out-of-band transmit energy of thetransmitter and/or to reject relatively large signal interferers inreceive path(s). These filters are often implemented by surface acousticwave (SAW) or bulk acoustic wave (BAW), such as film bulk acousticresonator (FBAR), technology. Such filters can include passivecomponents for tuning. These passive components can include one or moreshunt inductors to tune out the shunt capacitance of the filter. Currentsolutions can include about 8 to 16 separate filters, each having adedicated passive component for tuning. The separate filters can eachhave dedicated tuning, which can be expensive to implement and/orconsume physical area in a limited amount of space. Aspects of thisdisclosure relate to implementing tuning at a common node of an antennaswitch such that some or all of the tuning of separate passivecomponents can be eliminated and merged into a common tunable element.

Some previous systems included a separate passive tuning network for asignal path associated with each band of a plurality of bands. Spaceconstraints limited the optimization of such tuning networks in variousimplementations, thereby resulting in sub-optimal tuning and increasedinsertion loss.

Aspects of this disclosure relate to a contour tuning circuitelectrically connected to a common node of a multi-throw antenna switch.The contour tuning circuit can be a tunable filter that providesadjustable impedance matching. A common filter network can be integratedwithin an antenna switch element. The common filter network can includea shunt inductor in parallel with a tunable capacitance circuit at thecommon node of the multi-throw antenna switch. The tunable capacitancecircuit at the common node of the multi-throw antenna switch can adjustan impedance presented at the common node based on parasitics of theinterface to throws of the multi-throw antenna switch and/or filtercharacteristics associated with a selected throw of the multi-throwswitch that is activated. This can adjust impedance presented to afilter associated with a selected throw of the multi-throw switch thatis activated as desired.

In certain embodiments, an impedance at a common port of a multi-throwswitch can be tuned by adjusting an effective capacitance in parallelwith a shunt inductor coupled to the common port of the multi-throwswitch in association with a state of the multi-throw switch changing.This adjustment can include tuning a switch on to couple a capacitor inparallel with the shunt inductor. The shunt inductor and the tunablecapacitor can be coupled to a node is a signal path between the commonport and an antenna port.

The contour tuning circuits discussed herein can provide tunability suchthat a software interface can be used to tune each band rather thanmanually determining an impedance match for each band. This can reducethe time for determining respective states of the contour tuning circuitassociated with each band. The contour tuning circuits discussed hereincan consolidate most or all of the tuning elements into a common tuningelement of the contour tuning circuit. This can reduce the physical sizeand/or cost of an electronic component and/or an electronic system thatincludes the contour tuning circuits.

An antenna switch can selectively electrically couple a radio frequencysignal path to an antenna. The antenna switch can include a multi-throwswitch having respective throws coupled different duplexers. The antennaswitch can selectively electrically connect a particular duplexer to theantenna.

The antenna switch can be designed for a 50 Ohm interface. Routing oftraces between duplexers and the antenna switch can add a parasiticcapacitance in signal paths between respective duplexers and the antennaswitch. The duplexers can also contribute to the parasitic capacitance.Traces between the duplexers and the antenna switch can be implementedon or in a packaging substrate, such as a laminate substrate. The tracesbetween the duplexers and the antenna switch can introduce differentamounts of parasitic capacitance.

One approach to mitigating the parasitic capacitance of the tracesbetween the duplexers and the antenna switch is to match out suchparasitic capacitances with a shunt inductance at an output of eachduplexer. However, this approach can add cost and insertion loss.

Aspects of this disclosure relate to absorbing the routing capacitanceof the trances into a module that includes the antenna switch such thata 50 Ohm interface is presented at the duplexer impedance plane. Throughthe use of a tunable capacitance circuit within the module, theimpedance at a duplexer can be programmed such that transmit and receiveimpedance contours can be enhanced and/or optimized. According tocertain embodiments, a single shunt inductance can be electricallycoupled to a common node of the antenna switch. This shunt inductancecan be in parallel with the tunable capacitance circuit. The shuntinductance and the tunable capacitance circuit can match out parasiticsof routing between duplexers and an antenna switch.

FIG. 1A is a schematic diagram of a radio frequency (RF) system 10according to an embodiment. RF systems discussed herein can beconfigured to process radio frequency signals having a frequency in arange from about 300 kHz to 300 Glitz, such as in a range from about 450MHz to 6 GHz. As illustrated, the RF system 10 includes a contour tuningcircuit 12, duplexers 13 a to 13 n, an antenna switch 14, a filter 16,an antenna 17 arranged to transmit and receive RF signals, and a controlcircuit 18.

A tunable circuit can be coupled to a common port of a multi-throwswitch and adjust impedance at the multi-throw switch. Such a tunablecircuit can be referred to as a contour tuning circuit. The contourtuning circuit can provide tunable filtering by providing impedancematching that is adjustable. In FIG. 1A, the contour tuning circuit 12can adjust an impedance presented at a common port the antenna switch 14to enhance and/or optimize impedance contours at the duplexers 13 a to13 n. The contour tuning circuit 12 can be integrated with the antennaswitch 14 in a module. Such a module can be referred to as an antennaswitch module. The contour tuning circuit 12 includes a shunt inductorL1 in parallel with a tunable impedance circuit. The tunable impedancecircuit can be a capacitance circuit C_(T) as illustrated. According tosome other embodiments, the tunable impedance circuit can be any othersuitable tunable impedance circuit. The contour tuning circuit 12 iscoupled to a common port of the antenna switch 14. The common port ofthe antenna switch 14 can be referred to as a common node of the antennaswitch 14. The contour tuning circuit 12 can adjust an impedancepresented at a selected duplexer of the duplexers 13 a to 13 n that iselectrically connected to the contour tuning circuit 12 by way of theantenna switch 14. This can enhance and/or optimize transmit and receiveimpedance contours at the selected duplexer.

The tunable capacitance circuit C_(T) can adjust an effectivecapacitance that is in parallel with the shunt inductor L₁ to provideimpedance tuning associated with the selected duplexer. The tunablecapacitance circuit C_(T) can be arranged to provide a first effectivecapacitance in parallel with the shunt inductor L₁ when a first throw ofthe antenna switch 14 is active and to present a second effectivecapacitance in parallel with the shunt inductor L₁ when a second throwof the antenna switch 14 is active.

The shunt inductor L₁ can have an inductance so as to provide a desiredimpedance in combination with the tunable capacitance circuit C_(T). Theinductance of the shunt inductor L₁ can be selected so as to absorb asignificant amount of capacitance of the routing between the duplexers13 a to 13 n and the antenna switch 14. In certain embodiments, theshunt inductor L₁ can have an inductance in a range from about 4 nH to12 nH. For instance, the shunt inductor L₁ can have an inductance in arange from about 5 nH to 7 nH in some applications. In some otherapplications, the shunt inductor L₁ can have an inductance in a rangefrom about 9 nH to 11 nH.

While the contour tuning circuit 12 shown in FIG. 1A includes a shuntinductor L₁ in parallel with a tunable capacitance circuit C_(T), othersuitable contour tuning circuit topologies can be implemented inaccordance with any of the principles and advantages discussed herein.Other contour tuning circuit topologies can include any other suitablepassive impedance network that includes passive impedance elements inseries and/or parallel with each other. For instance, the illustratedshunt inductor L₁ can be implemented by an LC circuit or an RL, circuitin certain applications. As another example, the illustrated tunablecapacitance circuit C_(T) can be implemented by a tunable LC circuit ora tunable RC circuit in some applications. As one more example, acontour tuning circuit can include an RC circuit, an LC circuit, an RLcircuit, or an RLC circuit with any suitable combination of seriesand/or parallel passive impedance elements to implement contour tuningin accordance with any of the principles and advantages discussedherein.

The duplexers 13 a to 13 n can provide any suitable duplexingfunctionality. Each of the duplexers 13 a to 13 n can provide transmitfiltering and receive filtering for a particular frequency band. Anysuitable number of duplexers 13 a to 13 n can be implemented in the RFsystem 10. Each of the duplexers 13 a to 13 n can be coupled to a throwof the antenna switch 14.

The antenna switch 14 has multiple throws. The antenna switch 14 caninclude 8 or more throws in certain embodiments. For instance, theantenna switch 14 can include 10 to 12 throws in some embodiments. Theantenna switch 14 includes a common port. The antenna switch 14 alsoincludes a plurality of input/output (I/O) ports coupled to respectiveduplexers 13 a to 13 n. An I/O port can serve as an input port, anoutput port, or an input and output port. For instance, an I/O port canserve as an input of the antenna switch 14 for a transmission path andan output of the antenna switch 14 for a receive path. The antennaswitch 14 can electrically connect a selected I/O port to the commonport. This can electrically connect a selected duplexer to the antenna17. For instance, FIG. 1A illustrates a first I/O port I/O associatedwith a first duplexer 13 a electrically connected to the common port,which is electrically connected to the antenna 17 by way of the filter16.

The filter 16 is in a signal path between the common port of the antennaswitch module 14 and the antenna 19. The filter 16 can provide anysuitable filtering, in certain embodiments, the filter 16 includes a lowpass filter. According to some embodiments, the filter 16 can include anelliptic filter and a tunable notch filter.

The control circuit 18 can tune the tunable capacitance circuit C_(T) ofthe such that a desired impedance is in parallel with the series LCcircuit. For instance, the control circuit 18 can tune the tunablecapacitance circuit C_(T) so as to provide an impedance at the commonport of the antenna switch 14 for a selected I/O port of the antennaswitch 14. The control circuit 18 can set a state of the tunablecapacitance circuit C_(T) in accordance with any of the suitableprinciples and advantages discussed herein.

FIG. 1B is a schematic diagram of an illustrative tunable capacitancecircuit 19 according to an embodiment. The tunable capacitance circuit19 is an example of the tunable capacitance circuit C_(T) of FIG. 1A.The illustrated tunable capacitance circuit 19 includes a fixedcapacitor C_(P0) in parallel with a plurality of series circuits. Eachof the series circuits includes a capacitor in series with a switch. Asshown in FIG. 1B, the series circuits include a first capacitor C_(T1A)to C_(T4A) in series with a switch S_(T1) to S_(T4), respectively, and asecond capacitor C_(T1B) to C_(T4B), respectively. The capacitors of thetunable capacitance circuit 19 can have any suitable capacitance values.According to certain implementations, the fixed capacitor C_(P0) canhave a capacitance that is approximately equal to the capacitanceprovided by a series circuit when its switch electrically connectscapacitance in parallel with the fixed capacitor C_(P0). The seriescircuits can provide binary weighted capacitances in parallel with thefixed capacitor C_(P0) in some embodiments. The switches S_(T1) toS_(T4) can adjust the capacitance of the tunable capacitance circuit 19by switching-in and/or switching-out respective capacitors to adjust anamount of capacitance coupled in parallel with the fixed capacitorC_(P0).

In some other implementations, other suitable tunable capacitancecircuits can be implemented. For instance, a tunable capacitance circuitcan include one or more varactors, a tunable microelectromechanicalsystems (MEMS) capacitor, or any other suitable variable capacitancecircuit.

Any of principles and advantages of the contour tuning circuitsdiscussed herein can be implemented in any suitable application thatcould benefit from a contour tuning circuit, such as applications inwhich an impedance at a common port of a multi-throw switch can beadjusted based on which selected signal path connected to a multi-throwswitch is coupled to the common port of the multi-throw switch. Forinstance, a contour tuning circuit can be coupled between a common portof a multi-throw switch and a low noise amplifier. Such a contour tuningcircuit can be arranged to provide an impedance tuning associated withrouting of different signal paths from receive filters to a multi-throwswitch. A contour tuning circuit implemented in a receive signal pathshould not add insertion loss to any transmit signal path. FIGS. 2 and 3illustrate example radio frequency systems in which a contour tuningcircuit is implemented. Any combination of features of the contourtuning circuits discussed herein can be implemented in connection withany suitable principles and advantages discussed with reference to theradio frequency systems of FIGS. 2 and/or 3.

FIG. 2 is a schematic diagram of a radio frequency system 20 accordingto an embodiment. As illustrated, the RF system 20 includes a contourtuning circuit 12, receive filters 23 a to 23 n, a receive switch 24, alow noise amplifier 26, and a control circuit 28. The contour tuningcircuit 12 of FIG. 2 is in a signal path between the common port of thereceive switch 24 and the low noise amplifier 26. The receive switch 26can be a multi-throw switch arranged to electrically couple a selectedreceive filter to the low noise amplifier 26. Different receive filters23 a to 23 n can be arranged for processing RF signals within differentfrequency bands. For instance, the receive filters 23 a to 23 n can bebandpass filters with different pass bands. The receive filters 23 a to23 n can be implemented in duplexers, for example.

The control circuit 28 of FIG. 2 can set the state of the contour tuningcircuit 12 to correspond to a radio frequency signal path being coupledto the low noise amplifier 26. This can provide impedance tuning andaccount for different impedances corresponding to the different routingfrom the receive filters 23 a to the 23 n to the receive switch 24. Thetunability of the contour tuning circuit 12 can enable tuning fordesirable impedance matching for a plurality of different receivefilters using a common tuning circuit.

FIG. 3 is a schematic diagram of a radio frequency system 30 with acontour tuning circuit 12 according to another embodiment. Asillustrated, the RF system 30 includes a contour tuning circuit 12, RFsignal paths 33 a to 33 n, a multi-throw switch 34, an RF circuit 36,and a control circuit 38. The RF signal paths 33 a to 33 n can includeany suitable RF signal paths. The RF signal paths 33 a to 33 n caninclude, for example, duplexers, receive filters, transmit filters, RFamplifiers such as power amplifiers, or the like. The multi-throw switch34 can be any suitable multi-throw switch. The multi-throw switch 34 canbe, for example, an antenna switch, a receive switch, or any othersuitable RF switch. The RF circuit 36 can be a filter arranged to filterRF signals, an RF amplifier such as a low noise amplifier, an RF switch,or any other suitable RF circuit. The control circuit 38 can set thestate of the contour tuning circuit 12 to correspond to a radiofrequency signal path being coupled to the RF circuit 36. This canprovide impedance tuning and account for different impedancescorresponding to the different routing from the RF signal paths 33 a tothe 23 n to the multi-throw switch 34. The tunability of the contourtuning circuit 12 can enable tuning for desirable impedance matching fora plurality of different receive filters using a common tuning circuit.

As discussed above, an antenna switch can be designed for a 50 Ohminterface and routing of traces between duplexers and the antenna switchcan add different parasitic capacitances in respective signal paths. Acontour tuning circuit can be tuned to enhance and/or optimize impedancematching. More details will now be provided to regarding implementingcontour tuning between a common port of an antenna switch and an antennaport.

FIG. 4A is a Smith chart showing target duplexer antenna impedancesaccording to an embodiment. The target duplexer antenna impedances canrepresent design targets. As shown in FIG. 4A, the target impedances areshown for signal paths for the following frequency bands: Band 8, Band12, Band 13, Band 20, Band 26, Band 28A, and Band 28B.

Impedance matching at a duplexer antenna interface can involve a highlyinductive impedance. The highly inductive impedance can be implementedby a shunt inductor. However, relatively long signal routes (e.g.,conductive traces on a packaging substrate) can create capacitiveparasitic impedances.

FIG. 4B illustrates a portion of a module 37 with a trace 38 on apackaging substrate 39. The trace 38 is an example interconnect betweena duplexer and an antenna switch. The trace 38 can include the majorityof routing from an RF signal path associated with a frequency band to anantenna. Accordingly, the trace 38 can be referred to as an antennaroute. The illustrated trace 38 can be associated with Band 8 signalpath to an antenna switch. The trace 38 can be relatively long and canhave a parasitic capacitance that can be significant. Matching theparasitic capacitance associated with the trace 38 could involve aseries inductance of up to about 3 nH in some implementations. Thisvalue of inductance can require a relatively large amount of die area.Accordingly, a contour tuning circuit that can match parasiticcapacitance of traces to the antenna switch without a relatively largeseries inductance can be desirable. The contour tuning circuitsdiscussed herein can advantageously be used to implement impedancematching of parasitic capacitance without a series inductance in certainapplications.

Table 1 provides example capacitances for the trace impedances forsignal paths associated with different frequency bands. The capacitancescan be parasitic capacitances of traces between a duplexer associatedwith respective frequency band and an I/O port of an antenna switch. Thecapacitance value for Band 8 can be the capacitance value associatedwith the trace 38 of FIG. 4B, for example. The parasitic capacitances oftraces can range from about 0.5 pF to about 2.0 pF in certainimplementations. These parasitic capacitances typically depend on aphysical layout of a module. Some of the parasitic capacitancesassociated with different bands can be similar to each other and otherparasitic capacitances associated with different bands can vary by about1 pF or more in certain implementations.

TABLE 1 Frequency Band Antenna Trace Capacitance (pF) B8 1.3 B28B 0.6B28A 0.8 B27 1.6 B20 1.5 B13 0.9 B12 0.4 B26 0.9

One way of matching the capacitance of traces associated with each bandis to include a series inductor in a signal path between each duplexerand the antenna switch. Such a series inductor can have an inductance ofup to about 3 nH in certain applications. However, such an inductor canbe relatively large and/or relatively expensive to implement. The seriesinductor can be eliminated by absorbing routing capacitance into anantenna switch module, for example, using a contour tuning circuit inaccordance with the principles and advantages discussed herein.

A harmonic filter integrated on an antenna switch module can incorporatea shunt input capacitance. Such a shunt capacitance can be modified toabsorb the parasitic off state capacitance of the antenna switch of theantenna switch module. Accordingly, a capacitance and a physical size ofthis shunt capacitor can be decreased. Further modification of the shuntinput capacitance of the harmonic filter can absorb the parasitic boardcapacitance and translate the harmonic filter input impedance to aduplexer interface.

In certain applications, the total capacitance to be absorbed is largerthan a total harmonic filter input capacitance. Accordingly, a shuntinductance can be included at an interface between the antenna switchand the harmonic filter. This can enable more capacitance to beabsorbed. Such a technique is also applicable to a medium band (MB)signal path and a high band (HB) signal path, even though such signalpaths may not typically include a harmonic filter within an antennaswitch module.

A compensation capacitance can be disposed at each antenna switch I/Oport and a common switched capacitance array can be integrated inparallel with an input of a harmonic filter included in a signal pathbetween the antenna switch and an antenna port.

FIG. 5 is a schematic diagram of a radio frequency system 40 accordingto an embodiment. The illustrated radio frequency system 40 includes acontour tuning circuit 42, an antenna switch 44, antenna filtersincluding an elliptic filter 46 and a tunable notch filter 48, and anantenna 49. The RF system 40 can implement a switching function tocouple a selected signal path to the antenna 49. The RF system 40 canalso filter signals propagating between the antenna switch 44 and theantenna 49. The RF system 40 can also provide contour tuning at a commonnode N1 of the antenna switch. The illustrated contour tuning circuit 42is coupled between the common node N1 and a ground potential.

The illustrated antenna switch 44 is a multi-throw switch that includes10 throws. Some or all of these throws can be associated with differentfrequency bands. As illustrated, each throw includes a switch arm S1A toS10A and a shunt arm S1B to S10B. When a selected throw is activated,its shunt art can be off and its switch arm can be on to electricallyconnect a signal path connected to an I/O port of the throw to a commonnode N1 of the antenna switch 44. For instance, as shown in FIG. 5, thefirst series switch S1A is on and the first shunt switch S1B is off.This can couple the common node N1 to an I/O port associated with thefirst throw. Accordingly, the first throw is activated in the stateshown in FIG. 5. Inactive throws of the antenna switch can have theirswitch arms off and their shunt arms on. For instance, as shown in FIG.5, the series switch S2A to S10A are off and the shunt switches S2B toS10B are off. This can shunt the inactive I/O ports to a groundpotential. A control circuit (not illustrated) can control the seriesswitches and the shunt switches of the antenna switch 44 such that theantenna switch 44 is in a desired state.

The antenna switch 44 includes capacitors CP1 to CP10 coupled to I/Oports of the antenna switch 44. The capacitors CP1 to Cp10 are inparallel with the shunt arms S1B to S10B, respectively. Accordingly,when a shunt arm is off, the capacitor in parallel with the shunt armcan provide a shunt capacitance at an I/O port of the antenna switch 44.This shunt capacitance can provide course compensation capacitanceassociated with a signal path coupled to a respective throw of theantenna switch 44.

The antenna switch 44 also includes a resistor R1 and a switch SC inseries with the resistor R1. The switch SC can couple the common node N1to ground by way of the resistor R1. This can couple the common node N1to ground by way of resistor R1, for example, when all of the throws ofthe antenna switch 44 are inactive.

Some elements of the illustrated RF system 40 can be implemented on asemiconductor die, such as a silicon-on-insulator die, and otherelements of the RF system 40 can be implemented external to thesemiconductor die. For instance, capacitors and switches can beimplemented on the semiconductor die and inductors can be implementedexternal to the semiconductor die. The semiconductor die includescontacts (e.g., pins, bumps, pads such as wire bond pads, or the like)to provide electrical connections between circuit elements on thesemiconductor die and circuit elements external to the die. Any suitableelectrical connector can be implemented between a contact of thesemiconductor die and an element of the RF system 40 implementedexternal to the semiconductor die. For instance, an inductor can beelectrically connected to a contact of the die by way of a conductivetrace, a wire bond, the like, or any suitable combination thereof.

As illustrated in FIG. 5, the semiconductor die includes a plurality ofground contacts G1 to G7 to provide ground connections. Any suitablenumber of ground contacts can be implemented in some otherimplementations, FIG. 5 also illustrates contacts B27, B28, B13, B8,B28B, B12, 2G, B26, B20, and LB_DRx providing I/O ports for signal pathsassociated with different frequency bands. In particular, theillustrated contacts B27, B28, B13, B8, B28B, B12, 2G, B26, B20, andLB_DRx can be associated with Band 27, Band 28, Band 13, Band 8, Band28B, Band 12, 2G, Band 26, Band 20, and Low Band Drive Receive signalpaths. Any suitable number of contacts can provide RF signals associatedwith different signal paths. Such signal paths can be associated withany suitable frequency bands, signaling modes, power modes, the like, orany combination thereof. Contacts N2, N3, N4, N5, and ANT can couplecapacitors or other circuit elements of a semiconductor die to arespective inductor implemented external to the semiconductor die. Thecontact ANT can serve as an antenna port.

The illustrated contour tuning circuit 42 includes a shunt inductor L1and a tunable capacitance circuit. The tunable capacitance circuit andthe shunt inductor L1 can together effectively provide a desired shuntimpedance. The tunable capacitance circuit can tune a reactance providedfor relatively high Q and/or relatively low loss. The tunablecapacitance shown in FIG. 5 includes tuning capacitors CT1, CT2, and CT3each in series with a switch ST1, ST2, and ST3, respectively. The tuningcapacitors CT1, CT2, and CT3 can each be selected switched in orselectively switched out using switches ST1, ST2, and ST3, respectively.As shown in FIG. 5, switch ST2 is on and switches ST1 and ST3 are off Inthis state, tuning capacitor CT2 is coupled in parallel with the shuntinductor L1. The tuning capacitors can have capacitances in the rangefrom about 0.1 pF to about 2 pF, such as in the range from about 0.25 pFto about 1 pF, in certain implementations. The tuning capacitors canhave any suitable capacitances for implementing contour tuning inaccordance with the principles and advantages discussed herein. With thetuning capacitors CT1, CT2, and CT3 and respective switches ST1, ST2,and ST3, the tunable capacitance circuit is configurable into 8 states.In some other implementations, a different number of capacitors or othertunable elements can be implemented. For instance, 4 differentcapacitors can be switched in and switched out to implement 16 differentstates of a tunable capacitance circuit. A control circuit, such as thecontrol circuit 18 of FIG. 1A, can provide control signals to theswitches ST1, ST2, and ST3 such that the tunable capacitance circuitprovides a desired capacitance in parallel with the shunt inductor L1.

The elliptical filter 46 can function as a harmonic filter. Theelliptical filter 46 can function as a low pass filter. An ellipticalfilter can exhibit equalized ripple responses in both the pass band andthe stop band. Thus, the elliptical filter 46 can provide rejectionrelatively near and about the resonant frequency to create a stop bandwhich can suppress undesired signals that may occur. An ellipticalfilter can be desirable for providing harmonic frequency traps whilealso providing relatively low insertion loss in the pass band. Theillustrated elliptical filter 46 can provide a third harmonic frequencytrap and has a notch at about 5 GHz.

The illustrated elliptical filter 46 includes a parallel LC circuit thatincludes a capacitor C₁ in parallel with an inductor L₂. In theembodiment of FIG. 5, the parallel LC circuit is coupled in seriesbetween the common port of the antenna switch 44 and the tunable notchfilter 48. The parallel circuit can provide an open circuit at the thirdharmonic of an RF signal propagating between the common port of theantenna switch 44 and the antenna 49 and an impedance match at thefundamental frequency of the RF signal. The capacitance of the capacitorC₁ and the inductance of the inductor L₂ can be selected so as toachieve this functionality. As illustrated, the capacitor C₁ iselectrically coupled in parallel with the inductor L₂ by way of contactsN2 and N3.

The illustrated elliptical filter 46 also includes a series LC shuntcircuit. The series LC shunt circuit includes an inductor L₃ and acapacitor C₂. As illustrated, the capacitor C₂ is electrically connectedto the inductor L₃ by way of contact N4. The capacitor C2 and theinductor L3 can provide a notch at approximately 5 GHz. This can filterout a Wi-Fi signal having a frequency of approximately 5 GHz. Thecapacitance of the capacitor C₂ and the inductance of the inductor L₃can be selected so as to achieve a notch at 5 GHz. In some otherembodiments, the series LC shunt circuit that includes the inductor L₃and the capacitor C₂ can provide a notch at a different selectedfrequency.

The illustrated tunable notch tunable 48 can provide a notch in itsfrequency response at a selected frequency above the frequency of thecarrier, such as a second harmonic frequency. The frequency at whichharmonic rejection is provided can be tuned by adjusting the capacitanceof the tunable capacitance circuit CTN. The inductance and capacitancevalues of the series LC circuit of the tunable notch filter can beselected to match a resonant frequency of a large signal carrier andprovide an inductive effective impedance above the resonant frequency ofthe large signal carrier. The series LC circuit can be arranged topresent a low impedance at the frequency of a large signal carrier. Thiscan effectively short the tunable capacitance circuit CTN at thefrequency of the large signal carrier. At frequencies above a resonantfrequency of the series LC circuit of the tunable notch filter 48, theeffective impedance of the series LC circuit can become inductive. Thiseffective inductive impedance in parallel with the tunable capacitancecircuit CTN can create a parallel resonance that can be tuned to adesired frequency for rejection by tuning the capacitance of the tunablecapacitance circuit.

As shown in FIG. 5, the tunable notch filter 48 includes an inductorL_(S), a capacitor C_(S) in series with the inductor L_(S), and atunable capacitance circuit C_(TN). As illustrated, the inductor L_(S)has a first end electrically connected to the capacitor C_(S) by way ofcontact N5 and a second end electrically connected to the tunablecapacitance circuit C_(TN) by way of the contact ANT, which cancorrespond to an antenna port. As shown in FIG. 5, the inductor L_(S) isconnected between a second terminal of the capacitor C_(S) and a secondterminal of the tunable capacitance circuit C_(TN) by way of contacts N5and ANT, respectively. The antenna 49 is also connected to the contactANT in FIG. 5. The tunable capacitance circuit C_(TN) can be implementedby any suitable tunable capacitance circuit.

The illustrated tunable notch filter 48 can provide second harmonicrejection. Implementing a series circuit, such as the series LC circuitformed by the inductor L_(S) and the capacitor C_(S), in parallel with atunable capacitance circuit C_(TN) that includes switches to switch-inand switch-out capacitance can limit the signal swing across theswitches. For instance, less than about 1.4 Volts peak signal is presentacross switches of the tunable capacitance circuit C_(TN) in certainembodiments. According to some embodiments, less than about 1 Volt peaksignal is present across switches of the tunable capacitance circuitC_(TN). By limiting the voltage swing across the switches of the tunablecapacitance circuit C_(TN), the harmonic floor of the system can beimproved by preventing the switches from regenerating harmonics.

FIG. 6 is a schematic diagram of a model 60 of the radio frequencysystem 40 of FIG. 5 during operation. The model 60 illustrates models ofthe circuits of the radio frequency system 40. FIG. 6 illustratesparasitics associated with switches or other elements in the illustratedfilters and switch. As shown in FIG. 6, the impedance in a signal pathbetween an I/O port I/O and the antenna 49 can include a shuntcapacitance at an I/O port of an antenna switch, impedance associatedwith the antenna switch, impedance of the contour tuning circuit, andimpedance of the filters coupled in series with the contour tuningcircuit. With tuning of the contour tuning circuit, an impedance ofabout 50 Ohms can be presented at a duplexer port coupled to the antennaswitch. The model 60 illustrates impedances that can implement thecontour tuning in accordance with the principles and advantagesdiscussed herein.

A shunt capacitance model 62 illustrates a shunt capacitor CB associatedwith an active throw of an antenna switch. The shunt capacitor CB canrepresent any one of the capacitors CP1 to CP10 shown in FIG. 5. Forinstance, the shunt capacitance CB can represent the capacitor CP3 whenthe antenna switch 44 of FIG. 5 is passing a Band 13 signal. In FIG. 6,the shunt capacitor CB is coupled to an I/O port of the antenna switchthat is being electrically connected to the common port of the antennaswitch. The shunt capacitor CB can provide course band compensation tocompensate for trace capacitance in a signal path to the I/O port. Theshunt capacitor CB can have a capacitance value corresponding to a valuein Table 1 for a selected band in certain implementations. Thecapacitance value can be a selected value minus the value in Table 1 forthe selected band, for example. The shunt capacitor CB can have acapacitance of about a few pico-farads minus the trace capacitance.

An antenna switch model 64 illustrates that the antenna switch can bemodeled as a series resistance RASM and a parasitic capacitance CASM.The series resistance RASM can correspond to a resistance of a seriesswitch of the antenna switch being on. The series resistance RASM canrepresent an on state any one of the series switches S1A to S10A shownin FIG. 5. For instance, the series resistance RASM can represent theresistance of series switch S5A in an on state when the antenna switch44 of FIG. 5 is passing a Band 13 signal. The series resistance RASM canbe in a range from about 2 Ohm to 5 Ohms, for example. The parasiticcapacitance CASM of the antenna switch can represent off statecapacitances of inactive throws and/or capacitance of the selected throwbeing active. For instance, the antenna switch can have around 10 throwsthat are inactive while a selected through is active and parasiticcapacitance of the inactive throws (e.g., from shunt switches) canaffect the signal path to the antenna 49. The parasitic capacitance CASMof the antenna switch can be on the order of about 1 pF, for example.

A contour tuning circuit model 66 illustrates that a tunable capacitanceof the contour tuning circuit can be modeled as plurality of series RCcircuits in parallel with each other in certain states. Each capacitorof the tunable capacitance circuit switched-in with the common port ofthe antenna switch can be modeled as a resistance RON of a switch inseries with a tuning capacitor CT1 to CT3. FIG. 6 corresponds to a statein which 3 tuning capacitors CP1 to CT3 of a tunable capacitance circuitare electrically connected to the common port of the antenna switch. Inother states, a different numbers of tuning capacitors can beelectrically connected to the common port. The tuning capacitors canhave any suitable capacitance values to implement the contour tuningdiscussed herein. For instance, in certain implementations thecapacitances of tuning capacitors can be in a range from about 0.2 pF to3.2 pF, for example. The on resistances RON of the switches of thetunable capacitance circuit can be around 5 Ohms, for example.

An elliptic filter model 66 illustrates parasitic resistance RREF. Atunable notch filter model 69 illustrates parasitic resistance RTN.

FIG. 7 is a graph that illustrates relationships of insertion loss overfrequency for signal paths between a common port of an antenna switchand an antenna. A first curve 72 represents insertion loss associatedwith a notch filter. A second curve 74 represents insertion lossassociated with the notch filter and a contour tuning circuit accordingto an embodiment. A third curve 76 represents insertion loss associatedwith the antenna switch, the notch filter, and a contour tuning circuitaccording to an embodiment. The curves in FIG. 7 indicate that there isabout 0.25 dB of insertion loss associated with the contour tuningcircuit.

FIG. 8 is a Smith chart of transmit contour tune states of a tunablecapacitance circuit according to an embodiment. The contour tune statesare associated different states of the tunable capacitance circuit 19 ofFIG. 1B implemented in the radio frequency system 40 of FIG. 4 fortransmitting a signal in a particular frequency band. For example, thecurves in the illustrated Smith Chart are for transmit Band 20. Duringcalibration, each state of a tunable capacitance circuit can be tested.A lowest variation in impedance can be desired. Accordingly, the stateof the tunable capacitance circuit of a contour tuning circuitcorresponding to the innermost curve can be selected for the contourtuning circuit when a signal associated with the particular frequencyband is being transmitted. For instance, in FIG. 8, the state associatedwith the curve 82 can be selected for the frequency band associated withthis graph.

A state of tunable capacitance circuit of the contour tuning circuit(e.g., as shown in FIG. 5) can be set based at least partly on trimdata. The trim data can be stored in non-volatile memory, such as fuseelements (e.g., fuses and/or anti-fuses). For instance, the tunablecapacitance circuit can have 16 states in certain implementations. Insuch implementations, a control circuit can set the tunable capacitancecircuit into one of the 16 states by adding data representing 8 trimstates and 8 tuning state states. This can compensate for processvariations, such as process variations associated with the shuntinductor L1 of the contour tuning circuit and/or process variationsassociated with one or more capacitors of the tunable capacitancecircuit CT.

FIG. 9 is a schematic diagram of a model 100 of a signal path between aduplexer 102 and an antenna 49 in accordance with an embodiment. Themodel 100 is similar to the model 60 of FIG. 6, except that the model100 includes additional elements and excludes the shunt capacitancemodel 62. As shown in FIG. 10, a duplexer 102 can be coupled to an I/Ocontact I/O of a semiconductor die that includes an antenna switch. FIG.10 illustrates that the impedance in a signal path between the duplexer102 and the antenna 49 can include impedance in a signal path betweenthe duplexer and the I/O port I/O, impedance associated with the antennaswitch, impedance of the contour tuning circuit, and impedance of thefilters coupled in series with the contour tuning circuit. With tuningof the contour tuning circuit, an impedance of about 50 Ohms can bepresented at a duplexer port coupled to the antenna switch.

The duplexer 1002 is coupled to the I/O contact I/O by way of a seriesinductor 104 and a trace route 106. The series inductor 104 can beimplemented by a printable spiral inductor that can be implemented on asubstrate, such as a laminate substrate. The inductance of the seriesinductor 104 can be reduced due to the contour tuning circuit coupled toa common port of the antenna switch and still provide similar impedancematching as a larger inductance series inductor without the contourtuning circuit. The trace routing 106 can present impedance to thesignal path between the duplexer and the antenna switch. FIG. 1 aboveprovides examples of such parasitic routing capacitance. The contourtuning circuit can match out impedance of the trace routing 106 of aselected signal path.

The contour tuning circuit model 108 of FIG. 10 also illustrates that adifferent number of tuning capacitors can be switched in parallel withthe shunt inductor L1 than shown in model 66 of FIG. 6. In particular,the contour tuning circuit model 108 corresponds to 4 tuning capacitorsCT1 to CT4 being coupled in parallel with the shunt inductor L1 by wayof four respective switches.

FIG. 10 is a schematic diagram of a model 110 of a signal path between aduplexer 102 and an antenna 49 in accordance with another embodiment.The model 110 is similar to the model 100 of FIG. 10, except that themodel 110 includes a series capacitor 114 in place of a series inductor104. Accordingly, a series inductor can be eliminated from the signalpath from the duplexer 102 to the antenna switch. The series capacitor114 together with a contour tuning circuit can provide similar impedancematching as the series inductor and a contour tuning circuitcorresponding to the model 100 of FIG. 10. The series capacitor 114 canbe implemented at lower cost and/or reduce area relative to the seriesinductor 104.

FIG. 11A is a schematic diagram of an RF front end 120 according to anembodiment. An RF front end can include circuitry coupled between abaseband processor and an antenna. For instance, an RF front end caninclude circuitry coupled between a mixer and an antenna. An RF frontend can be coupled between a transceiver and an antenna. The RF frontend 120 can include one or more contour tuning circuits in accordancewith the any principles and advantages discussed herein.

As illustrated, the RF front end 120 includes power amplifiers 122 and123, matching networks 124 and 125, RF switches 126 and 127, duplexfilters 128, receive signal paths 129, an antenna switch 130, antennafilters 132, and antenna 134. The first power amplifier 122 and thesecond power amplifier 123 can be associated with different frequencybands and/or different triodes of operation. Each of these poweramplifiers can amplify RF signals. Matching networks 124 and 125 provideimpedance matching for outputs of power amplifiers 122 and 123,respectively, to reduce reflections and to improve signal quality.

The RF switch 126 can electrically connect the output of the first poweramplifier 122 to a selected transmit filter of the duplex filters 128.Similarly, the RF switch 127 can electrically connect the output of thesecond power amplifier 123 to a selected transmit filter of the duplexfilters 128. The RF switch 126 and/or the RF switch 127 can be amulti-throw switch.

The receive paths 129 can include a low noise amplifier and amulti-throw switch to electrically connect the low noise amplifier to aselected receive filter of the duplex filers 128.

An antenna switch 130 can be coupled between the duplex filters 128 andantenna filters 132. The antenna switch 130 can include a multi-throwswitch to electrically couple a selected duplexer in the duplex filters128 to the antenna 134. The duplex filters 128 can include a pluralityof duplexers. Each of these duplexers can include a transmit filter anda receive filter. The antenna filters 132 are coupled between the duplexfilters 128 and the antenna 134. The antenna 134 can be an antenna of amobile device, such as a mobile phone.

The antenna filters 132 can filter radio frequency signals propagatingbetween the antenna switch 130 and the antenna 134. The antenna filters132 can include a contour tuning circuit in accordance with any of theprinciples and advantages discussed herein. For instance, routingbetween the duplex filters 128 and the antenna switch 130 can vary fromsignal path to signal path. The antenna filters 132 can include atunable filter arranged to filter a radio frequency signal propagatingbetween a switch and an antenna port. The tunable filter can include acontour tuning circuit. A contour tuning circuit can present animpedance to provide impedance matching associated with routing of asignal path selected by the antenna switch 130. The antenna filters 132can be integrated into an antenna switch module that includes theantenna switch 130 in certain embodiments. The antenna filters caninclude any suitable filter arranged to filter RF signals propagatingbetween the antenna switch and the antenna 134. The antenna filters caninclude a harmonic filter and a tunable notch filter in certainembodiments. The tunable notch filter can be tuned so as to provide anotch at a second harmonic of a signal propagating between the antennaswitch 130 and the antenna 134.

FIG. 11B is a schematic diagram of an RF front end 140 according to anembodiment. The RF front end 140 is like the RF front end 120 exceptthat the RF front end 140 illustrates more detail of a receive paths andless detail of transmit paths. FIG. 11B shows that transmit paths 146are in communication with the duplex filters 128. The receive paths inFIG. 11B are similar to RF signal paths shown in FIG. 2. As shown inFIG. 11B, the duplex filters 128 can be coupled to a receive switch 142.The illustrated receive switch 142 is a multi-throw switch withdifferent throws connected to different respective duplexers of theduplexer filters 128. A contour tuning circuit 12 is coupled to a in asignal path between a common port of the receive switch 142 and a lownoise amplifier 144. The contour tuning circuit 142 can implement anysuitable combination of features of the contour tuning circuitsdiscussed herein. The transmit paths 146 can include one or more poweramplifiers. The transmit paths 146 can implement any suitablecombination of features of the transmit paths of the RF front end 120 ofFIG. 11A. In some embodiments, the transmit paths 146 can include apower amplifier and a multi-throw switch configured to couple an outputof the power amplifier to a selected signal path for processing.

FIG. 12 is a schematic block diagram showing more details of antennafilters according to an embodiment. The antenna filters 150 of FIG. 12are an example of the antenna filters 132 of FIG. 11A and/or FIG. 11B.One or more filters can be electrically coupled between the contourtuning circuit 152 and the antenna 134. As shown in FIG. 12, a harmonicfilter 154 and a tunable notch filter 156 can be electrically coupledbetween the contour tuning circuit 152 and the antenna 134. The harmonicfilter 154 and the notch filter 156 can reduce and/or eliminate harmonicdistortion from signals propagating between the antenna switch 130 andthe antenna 134. The harmonic filter 154 can implement one or morefeatures of the elliptic filter 46 of FIG. 5, for example. In some otherimplementations, the harmonic filter 154 can implement any suitableharmonic filtering. The tunable notch filter 156 can implement one ormore features of the tunable notch filter 48 of FIG. 5, for example. Insome other implementations, the tunable notch filter 156 can implement astatic notch filter or any other suitable notch filter.

FIG. 13 is a schematic block diagram of a module 160 according to anembodiment. The illustrated module 160 includes an antenna switch 130and a contour tuning circuit 152. The module 160 can be referred to asan antenna switch module. In the module 160, a contour tuning circuit inaccordance with any of the principles and advantages discussed hereincan be integrated with an antenna switch 130 within a common package.The contour tuning circuit 152 can be on the same packaging substrate asthe antenna switch 130. Some or all of the circuitry of the contourtuning circuit 152 can be integrated on the same die as the antennaswitch 130.

FIG. 14 is a schematic block diagram of a module 170 according to anembodiment. The illustrated module 170 includes a packaging substrate172 on which a power amplifier 122, a matching network 124, a switch(e.g., a band select switch) 126, duplex filters 128, an antenna switch130, and antenna filters 132 that include a contour tuning circuit arearranged. The illustrated elements can be enclosed within a commonpackage. In some other embodiments, the antenna filters 132 can beimplemented in a module and packaged with one or more of the illustratedelements of FIG. 14. Switches of the antenna switch 130 and/or ofembodiments of the contour tuning circuit of the antenna filters 132 canbe implemented in semiconductor-on-insulator technology such assilicon-on-insulator technology. The packaging substrate can be alaminate substrate in certain embodiments.

FIG. 15 is a schematic diagram of a packaged module 180 according to anembodiment. Aspects of this disclosure can be implemented in thepackaged module 180. The packaged module 180 includes a semiconductordie 182 and a shunt inductor L₁ on a packaging substrate 184 enclosedwithin a common package. The packaged module 180 can include one or moreother passive components on the packaging substrate in certainimplementations. Some such packaged modules can be multi-chip modules.The semiconductor die 182 can be manufactured using any suitable processtechnology. As one example, the semiconductor die 182 can be asemiconductor-on-insulator die, such as a silicon-on-insulator die.

As shown in FIG. 15, the packaged module 180 includes the semiconductordie 182 and the shunt inductor L₁ on the packaging substrate 184. Thesemiconductor die 182 can include a multi-throw switch 185 and thetunable capacitance circuit C_(T). The multi-throw switch 185 can bearranged, for example, as an antenna switch or as a select switcharranged to couple a selected receive filter to a low noise amplifier.The shunt inductor L₁ can be implemented as a spiral trace on thepackaging substrate 184 or in any other suitable manner to provide adesired inductance. The packaging substrate 184 can be a laminatesubstrate, for example.

Tunable Notch Filter

Carrier Aggregation in cellular networks has been a driver forsignificant improvement in transmit harmonic levels such that atransmitter of a mobile device, such as a smart phone, may notsignificantly degrade the sensitivity of the receiver of the mobiledevice in certain applications. In an effort to avoid degradinginsertion loss and implement additional filtering, it can be desirableto have a filter with tunable characteristics that can target higherrejection during specific operating modes. However, tuned elements ofsuch a filter can regenerate harmonics in a large signal environment.This can limit the effective harmonic floor of the electronic system.This disclosure provides a tunable filter with a tuned network that cansignificantly reduce the large signal amplitude presented to the tunedelement and cause the harmonic floor of the filter to be improved.

Some previous systems included fixed filter responses and would tradeinsertion loss for improved rejection. Other tunable filters havingtuning elements with limited dynamic range can provide a small signalsolution, but such tunable filters can have degraded performance forlarge signals, such as signals provided to an antenna for wirelesstransmission. A large signal can be a signal having a power of at least15 decibel-milliwatts (dBm). In some instances, a large signal can havea power of at least 20 dBm.

Aspects of this disclosure relate to a tunable filter with aseries/parallel resonant network that is tuned such that a seriesresonance circuit is arranged in parallel with a tuning element. Theseries resonance circuit can be a series LC circuit. The inductance andcapacitance vales of the series resonant circuit can be selected tomatch a resonant frequency of a large signal carrier and provide aninductive effective impedance above the resonant frequency of the largesignal carrier. The series resonance circuit can be arranged to presenta low impedance at the frequency of a large signal carrier. This caneffectively short the tuning element at the frequency of the largesignal carrier. Accordingly, a relatively low voltage swing can bepresent across the tuning element. At frequencies above a resonantfrequency of a series resonance circuit of the tunable filter, theeffective impedance of the series resonance circuit can becomeinductive. This effective inductive impedance in parallel with thetuning element can create a parallel resonance that can be tuned to adesired frequency for rejection by tuning the tuning element. The tuningelement can be, for example, a tunable capacitance circuit. The tunablefilter can provide, for example, rejection at a second harmonic of alarge signal carrier.

In certain embodiments, a tunable filter in accordance with theprinciples and advantages discussed herein can be coupled in series in asignal path between an antenna switch and an antenna port. The tunablefilter can be in series with a low pass filter between the antennaswitch and the antenna port. The tunable filter can be a tunable notchfilter. The tunable filter can include a series LC circuit in parallelwith a tunable impedance circuit, such as a tunable capacitance circuit.The impedance of the tunable impedance circuit can be adjusted such thatthe tunable filter provides a desired characteristic for a signal beingprovided from the antenna switch module to the antenna port. Forinstance, the antenna switch module can include a multi-throw switchand, depending on a frequency band associated with a throw of themulti-throw switch that is activated, the tunable impedance circuit canbe set to a state that results in rejection of a second harmonicassociated with the frequency band of the activated throw of themulti-throw switch.

According to some other embodiments, a tunable filter in accordance withthe principles and advantages discussed herein can be implemented tofilter an output of a power amplifier. In such embodiments, the tunablefilter can reduce harmonics in signals amplified by the power amplifier.

Advantageously, the tunable filters discuss herein can providetunability in a large signal environment. Insertion loss to a desiredcarrier can be relatively low due to relatively high quality factor (Q)series resonance (e.g., a Q of greater than 20), while 20 dB or more ofrejection can be introduced at frequencies above the frequency of alarge signal carrier in certain embodiments. The tunable filtersdiscussed herein can address difficulties in suppressing harmonics incarrier aggregation applications.

FIG. 16 is a schematic diagram of a radio frequency (RF) system 210 thatincludes a tunable notch filter 212 according to an embodiment. RFsystems discussed herein can be configured to process radio frequencysignals having a frequency in a range from about 30 kHz to 300 GHz, suchas in a range from about 450 MHz to 6 GHz. As illustrated, the RF system210 includes a tunable notch filter 212, an antenna switch 214, a filter216, a control circuit 218, and an antenna 219 arranged to transmit andreceive RF signals. An antenna switch module can include the antennaswitch 214 and control circuitry associated with the antenna switch 214.The antenna switch module can include the tunable notch filter 212integrated with the antenna switch 214. The tunable notch filter 212 andthe antenna switch 214 can be included within a common package. Theantenna switch 214 and at least a portion of the tunable filter 212 canbe implemented on a common semiconductor die.

The antenna switch 214 has multiple throws. The antenna switch 214 canin 8 or more throws in certain embodiments. For instance, the antennaswitch 214 can include 10 to 12 throws in some embodiments. The antennaswitch 214 includes a plurality of input/output (I/O) ports I/O PORT₁ toI/O PORT_(N) and a common port COMMON PORT. An I/O port can serve as aninput port, an output port, or an input and output port. For instance,an I/O port can serve as an input of the antenna switch 214 for atransmission path and an output of the antenna switch 214 for a receivepath. The antenna switch 214 can electrically connect a selected I/Oport to the common port. For instance, FIG. 16 illustrates a first I/Oport I/O PORT₁ electrically connected to the common port COMMON PORT.The antenna switch 214 can activate a throw to electrically connect anI/O port to the common port.

The filter 216 is in a signal path between the common port of theantenna switch 214 and the antenna 219. The filter 216 can provide anysuitable filtering. In certain embodiments, the filter 216 is a low passfilter.

As illustrated in FIG. 16, the tunable notch filter 212 is in serieswith the filter 216 in the signal path between the common port of theantenna switch 214 and the antenna 219. The illustrated tunable notchfilter 212 includes a series resonant circuit in parallel with a tunableimpedance circuit. As illustrated, the series resonant circuit is aseries LC circuit that includes a capacitor C_(S) in series with aninductor L_(S). The tunable impedance circuit can be a tunablecapacitance circuit C_(PT). The series LC circuit can effectively shortthe tunable impedance circuit at a frequency of a radio frequency signalpropagating between the common port of the antenna switch 214 and theantenna 219. The series LC circuit can be inductive at frequencies abovea resonant frequency of the series LC circuit, and the series LC circuitcan create a parallel resonance with the tunable impedance circuit toprovide a notch of the tunable notch filter 212. The tunable notchfilter 212 can provide a notch at a harmonic, such as a second harmonic,of the radio frequency signal propagating between the common port of theantenna switch 214 and the antenna 219.

While the tunable notch filter 212 shown in FIG. 16 includes a series LCcircuit in parallel with a tunable capacitance circuit, other suitabletunable notch filter topologies are possible. Other tunable notch filtercircuit topologies can include any other suitable passive impedancenetwork that includes passive impedance elements in series and/orparallel with each other. For instance, the illustrated tunablecapacitance circuit C_(PT) can be implemented by a tunable LC circuit ora tunable RC circuit in certain applications.

The antenna switch 214 can be configurable into states in which aselected throw is activated to electrically connect a selected I/O portto the common port. The other throws can be deactivated while theselected throw is activated. In different states of the antenna switch214, different I/O ports are electrically connected to the common portof the antenna switch 214. Two or more different I/O ports can beassociated with different frequency bands. The control circuit 218 cantune the tunable impedance circuit such that a desired impedance is inparallel with the series LC circuit. For instance, the control circuit218 can tune the tunable impedance circuit so as to provide a notch fora frequency band associated with an I/O port of the antenna switch 214that is selected.

FIG. 17A is a schematic diagram of a tunable notch filter 220 accordingto an embodiment. The tunable notch filter 220 is an example of thetunable notch filter 212 of FIG. 16. As illustrated, the tunable notchfilter 220 includes a series LC circuit in parallel with a tunablecapacitance circuit. The series LC circuit includes a capacitor C_(S) inseries with an inductor L_(S) between an input port IN and an outputport OUT. The tunable notch filter 220 can filter signals propagatingfrom the input port IN to the output port OUT and/or signals propagatingfrom the output port OUT to the input port IN. The tunable capacitancecircuit includes a plurality of switches S1 to S4 each in series with arespective capacitor C_(P1) to C_(P1). The switches S1 to S4 can adjustthe capacitance of the tunable capacitance circuit by switching-inand/or switching-out respective capacitors C_(P1) to C_(P4) to adjust anamount of capacitance coupled in parallel with a fixed capacitor C_(P0)that is in parallel with the series LC circuit. In some otherembodiments, switches can be implemented on opposing sides of acapacitor of the tunable capacitance circuit.

FIG. 17B is a graph showing a relationship of impedance versus frequencyfor the notch filter 220 of FIG. 17A. The graph of FIG. 17B plots theimpedance of the series LC circuit of the tunable notch filter 220 overfrequency. This graph shows that the series LC circuit can resonate at afrequency located at point 222 corresponding to a frequency of acarrier. This can effectively short the input port IN of the tunablenotch filter 220 to the output port OUT of the tunable notch filter 220at the frequency of the carrier. In the graph of FIG. 17B, the resonantfrequency of the series LC circuit is about 1 GHz. The capacitance ofthe capacitor Cs and the inductance of the inductor Ls can be selectedsuch that the series LC circuit can have any suitable resonantfrequency. According to certain implementations, the resonant frequencyof the series LC circuit can be in a range from about 700 MHz to 900MHz. In some implementations, the capacitance of the capacitor C_(S) canbe in a range from around 7 pF to 10 pF and the inductance of theinductor L_(S) can be in a range from around 2 nH to 4 nH.

As shown in FIG. 17B, at points on the illustrated curve below theresonant frequency of the series LC circuit (e.g., at point 224), theimpedance of the series LC circuit can be capacitive. As also shown inFIG. 17B, at points on the illustrated curve above the resonantfrequency of the series LC circuit (e.g., at point 226 at a secondharmonic of the resonant frequency), the impedance of the series LCcircuit can be inductive. For example, at point 226, the effectiveinductance of the series LC circuit can be around a few nanohenries.

FIG. 17C is a schematic diagram illustrating that a series LC circuit ofthe notch filter of FIG. 17A is inductive at a frequency above theresonant frequency of the series LC circuit. As shown in FIG. 17B, theseries LC circuit of the tunable notch filter 220 of FIG. 17A can havean inductive impedance at frequencies above the resonant frequency ofthe series LC circuit (e.g., at point 226 on the graph of FIG. 17B).FIG. 17C illustrates that the series LC circuit of the notch filter canbehave as an inductance L_(EFF) at frequencies above the resonantfrequency of the series LC circuit.

In the tunable notch filter 220, the tunable capacitance circuit inparallel with the series LC circuit can provide harmonic rejection. Thefrequency at which harmonic rejection is provided can be tuned byadjusting the capacitance of the tunable capacitance circuit. FIG. 17Dis a graph illustrating a relationship of impedance versus frequencyassociated with the tunable notch filter of FIG. 17C. The impedance inthis graph represents a series/parallel frequency response of thetunable notch filter. FIG. 17D shows that the tunable notch filter 220can provide rejection at second harmonic of a carrier and that there isa low loss at the frequency of the carrier. In particular, at point 232of the illustrated curve, a parallel resonance of the inductiveimpedance L_(EFF) of the series LC circuit and a tuned capacitanceprovide rejection. The frequency at which harmonic rejection is providedcan be at a second harmonic of a carrier, for example. Additionally, atpoint 234 on the illustrated curve, a low loss can be achieved at thefrequency of the carrier.

FIG. 17E is a schematic diagram of a tunable notch filter 236 accordingto another embodiment. The tunable notch filter 236 is an example of thetunable notch filter 212 of FIG. 16. As shown in FIG. 17E, the tunablenotch filter 236 includes a tunable capacitance circuit 238 thatincludes varactors. A tuning voltage V_(TUNE) can be applied to thevaractors to adjust capacitance in with parallel with a series LCcircuit. Varactors can have a higher Q factor than some other tunablecapacitance circuits. A servo loop can be implemented in connection witha varactor based tunable capacitance circuit to compensate fortemperature dependence of varactors. In some other embodiments, atunable capacitance circuit can include a different number of varactors,a tunable microelectromechanical systems (MEMS) capacitor, or any othersuitable variable capacitance circuit.

FIG. 18A is a schematic diagram of an antenna filter assembly 240 thatincludes a tunable notch filter 242 according to an embodiment. Theantenna filter assembly 240 can be coupled between an antenna switch andan antenna 241. The tunable notch filter 242 is an example of thetunable notch filter 212 of FIG. 16. Any of the principles andadvantages of the tunable notch filter 242 can be implemented inconnection with any of the tunable notch filters discussed herein. Theillustrated antenna filter assembly 240 includes the tunable notchfilter 242 and a low pass filter (LH) 243.

Some elements of the illustrated antenna filter assembly 240 can beimplemented on a semiconductor die, such as a silicon-on-insulator die,and other elements of the antenna filter assembly 240 can be implementedexternal to the semiconductor die. For instance, capacitors and switchescan be implemented on the semiconductor die and inductors can beimplemented external to the semiconductor die. The semiconductor dieincludes contacts (e.g., pins, bumps, pads such as wire bond pads, orthe like) to provide electrical connections between circuit elements onthe semiconductor die and circuit elements external to the die. Asillustrated in FIG. 18A, the semiconductor die includes contacts 244 and245 associated with the tunable notch filter 242 and contacts 246, 247,248, and 249 associated with the LPF 43. Any suitable electricalconnector can be implemented between a contact of the semiconductor dieand an element of the antenna filter assembly 240 implemented externalto the semiconductor die. For instance, an inductor can be electricallyconnected to a contact of the die by way of a conductive trace, a wirebond, the like, or any suitable combination thereof.

The illustrated LPF 243 is arranged as an elliptical filter. Anelliptical filter can exhibit equalized ripple responses in both thepass band and the stop band, and can thus provide rejection relativelynear and about the resonant frequency to create a stop band which cansuppress undesired signals that may occur. An elliptical filter can bedesirable for providing harmonic frequency traps while also providingrelatively low insertion loss in the pass band. The illustrated LPF 243can operate as an elliptical filter to provide a third harmonicfrequency trap and has a notch at about 5 GHz.

The LPF 243 includes an inductor L21 and a capacitor C21 connectedbetween the I/O port I/O and ground. The inductor L21 and the capacitorC21 are electrically connected by way of the contact 248. The inductorL21 and the capacitor C21 can have impedances selected so as to absorban off state capacitance associated with an antenna switch. Thecapacitance of the capacitor C21 of the LPF 243 can be in parallel withparasitic capacitance of a multi-throw switch of an antenna switchmodule. Accordingly, the capacitance of C21 can be reduced b e amountcorresponding to a parasitic capacitance of the multi-throw switch ofthe antenna switch module. By arranging C21 in parallel with parasiticcapacitance of the multi-throw switch, the physical size of C21 can bereduced. Series capacitors can be used to implement one or more of thecapacitors in the antenna filter assembly 240. This can limit voltageacross a particular capacitor.

The LPF 243 also includes a parallel LC circuit that includes acapacitor C2 in parallel with an inductor L22. The parallel LC circuitis coupled in series between the I/O port I/O and the tunable notchfilter 242. The parallel LC circuit can provide an open circuit at thethird harmonic of an RF signal propagating between the I/O port I/O andthe antenna 241 and an impedance match at the fundamental frequency ofthe RF signal. The capacitance of the capacitor C22 and the inductanceof the inductor L22 can be selected so as to achieve this functionality.As illustrated, the capacitor C22 is electrically coupled in parallelwith the inductor by way of contacts 246 and 247.

The LPF 243 also includes an inductor L23 and a capacitor C23 connectedbetween an internal node Node 1 and ground. The capacitor C23 iselectrically connected to the inductor L23 by way of contact 249. Thecapacitor C23 and the inductor L23 can provide a notch at approximately5 GHz. This can filter out a Wi-Fi signal having a frequency ofapproximately 5 GHz. The capacitance of the capacitor C23 and theinductance of the inductor L23 can be selected so as to achieve a notchat 5 GHz. In some other embodiments, the series LC circuit that includesthe inductor L23 and the capacitor C23 can provide a notch at adifferent selected frequency.

As shown in FIG. 18A, the tunable notch filter 242 includes an inductorL_(S), a capacitor C_(S) in series with the inductor L_(S), and atunable capacitance circuit C_(PT). As illustrated, the series inductorL22 has a first end electrically connected to the capacitor C_(S) by wayof contact 244 and a second end electrically connected to the tunablecapacitance circuit C_(PT) by way of the contact 245. A first terminalof the series capacitor C_(S) and a first terminal of the tunablecapacitance circuit C_(T) are connected to the internal node Node 1 inFIG. 18A. As shown in FIG. 18A, the series inductor L_(S) is connectedbetween a second terminal of the series capacitor C_(S) and a secondterminal of the tunable capacitance circuit C_(PT) by way of contacts244 and 245, respectively. The antenna 241 is also connected to thecontact 245 in FIG. 18A. The tunable capacitance circuit C_(PT) can beimplemented in accordance with any of the principles and advantages ofany of the tunable capacitance circuits discussed herein, such as thetunable capacitance circuit of FIG. 17A.

The illustrated tunable notch filter 242 can provide second harmonicrejection. Implementing a series LC circuit, such as the series LCcircuit formed by the series inductor L_(S) and the series capacitorC_(S), in parallel with a tunable capacitance circuit C_(PT) can limitthe signal swing across tuning switches of the tunable capacitancecircuit C_(PT). For instance, less than about 1.4 Volts peak signal ispresent across switches of the tunable capacitance circuit C_(PT) incertain embodiments. According to some embodiments, less than about 1Volt peak signal is present across switches of the tunable capacitancecircuit C_(PT). Switches of the tunable capacitance circuit C_(PT) canregenerate harmonics in a large signal environment and limit theeffective harmonic floor of the system. By limiting the voltage swingacross the switches of the tunable capacitance circuit C_(PT), theharmonic floor of the system can be improved.

FIG. 18B is a schematic diagram of an antenna filter assembly 250including a tunable antenna filter 253 according to another embodiment.The filter assembly 250 is like the filter assembly 240 except that theseries capacitor C_(S) of the tunable notch filter 242 of FIG. 18A isreplaced by a tunable capacitance circuit C_(ST) in the tunable notchfilter 253 of FIG. 18B. With the tunable capacitance circuit C_(ST), thetunable notch filter 253 can adjust a frequency at which the series LCcircuit that includes the tunable capacitance circuit C_(ST) and theinductor L_(S) resonates. This can also adjust the frequency at whichthe series LC circuit behaves as an inductive impedance instead of acapacitive impedance. In certain embodiments, the tunable capacitancecircuit C_(ST) can be implemented such that it adds less than about 0.5dB of insertion loss relative to the capacitor C_(S) of FIG. 18A. Thetunable capacitance circuit C_(ST) can be implemented in accordance withany of the principles and advantages of any of the tunable capacitancecircuits discussed herein.

FIG. 19 is a graph showing plots of insertion loss versus frequency fora tunable antenna filter according to an embodiment. This graph includescurves corresponding to selected antenna switch module signal pathsillustrating insertion loss associated with states of the tunable notchfilter 242 of FIG. 18A. A notch at the second harmonic can be tuned byadjusting capacitance in a tunable capacitance circuit that is inparallel with a series LC circuit based on a selected antenna switchmodule signal path. Any suitable control circuit, such as the controlcircuit 218 of FIG. 16, can tune the tunable capacitance circuit. Thecurve 262 corresponds to Long Term Evolution (LTE) Band 12 and has anotch that is at a frequency between 1.4 GHz and 1.5 GHz. The curve 263can correspond to LTE Band 13 and has a notch around 1.5 GHz. Curves264, 265 and 266 correspond to LTE Bands 26, 20, 8, respectively, andhave notches at the second harmonics for respective frequency bands.Curve 267 corresponds to LBDIV.

FIG. 20 is a graph showing plots of filter response versus frequency fora tunable antenna filter according to an embodiment. This graph showscurves illustrating frequency responses of states of the tunable notchfilter 242 of FIG. 18A. These curves indicate that notch depth decreasesas the notch frequency gets closer to the passband. The edge of thepassband can be indicated by the vertical line 268 at frequency M2. Anexample of notch depth is shown by vertical line 269 at frequency M3where the notch depth has approximately −20 dB of attenuation. As shownin FIG. 20, the tunable notch filter 242 can have more than 20 dB ofrejection for notches at frequencies above 1.5 GHz.

FIG. 21 is a graph showing plots of insertion loss versus frequency foran antenna switch and a tunable antenna filter according to anembodiment. This graph plots insertion loss versus frequency for anantenna switch module and the antenna filter assembly 240 of FIG. 18A.The plots indicate that there is less than 1 dB of insertion loss at 960MHz independent of the state of the tunable notch filter.

The series LC circuit of tunable notch filters discussed herein canexperience process variations. The capacitance of the capacitor C_(S) ofthe series LC circuit can vary from die to die. Alternatively oradditionally, the inductance of the inductor L_(S) of the series LCcircuit can vary from module to module. Process variations can degradethe effectiveness of a tunable notch filter. To reduce such degradation,trimming can be implemented. Accordingly, a state of tunable impedancecircuit of any of the tunable notch filters discussed herein can be setbased at least partly on trim data.

FIG. 22 is a schematic diagram of a radio frequency system 270 thatincludes a tunable notch filter 212 and a trim and control circuit 272according to an embodiment. The radio frequency system 270 is like theradio frequency system 210 of FIG. 16 except that the control circuit218 of FIG. 16 is replaced by a trim and control circuit 272 in FIG. 22.The trim and control circuit 272 can implement any of the functions forcontrolling a tunable impedance circuit, such as a tunable capacitancecircuit, discussed herein. The trim and control circuit 272 can use trimdata to set the state of a tunable impedance circuit. The trim data canrepresent a process variation associated with one or more circuitelements of the tunable notch filter 212. For instance, the trim datacan represent process variation(s) associated with the capacitor C_(S)and/or the series inductor L_(S) of the tunable notch filter 212. Thetrim data can be used to shift a frequency response of the tunable notchfilter so as to compensate for a process variation of one or morecircuit elements of the tunable notch filter 212. For instance, usingthe trim data, the trim and control circuit 272 can compensate forprocess variations of the series LC circuit of the tunable notch filter212.

FIG. 23 is a schematic diagram of a trim and control circuit 280according to an embodiment. The trim and control circuit 280 is anexample of the trim and control circuit 272 of FIG. 22 and can beimplemented in connection with any of the tunable filters and/or tunablecircuits discussed herein. The trim and control circuit 280 can set thestate of a tunable impedance circuit, such as the tunable capacitancecircuit of the tunable filter 220 of FIG. 17C, based on trim data andtuning state data. A trim and control circuit can implement any suitablenumber of trim states and any suitable number of notch tuning states.

As illustrated, the trim and control circuit 280 includes a firstregister 281, a data multiplexer 282, an inverter 283, an AND gate 284,an AND gate 285, a first fuse block 286, a second fuse block 287, afirst adder 288, a second adder 289, and a second register 290. Thefirst register 281 can provide signals to the data mux 282 and controllogic including the inverter 283 and AND gates 284 and 285 to store thetrim data to the first fuse block 286 or the second fuse block 287. Thefuse blocks 286 and 287 each include fuse elements (e.g., fuses and/oranti-fuses). In certain implementations, the fuse elements can beimplemented using semiconductor-on-insulator, such assilicon-on-insulator technology. Such fuse elements can be implementedby eFUSE technology. According to some other implementations, the trimdata can be stored in another suitable type of non-volatile memory.

The illustrated trim and control circuit 280 can set a tunable notchfilter into 16 states. Each of the fuse blocks 286 and 287 shown in FIG.23 is arranged to store 3 bits of trim data. Accordingly, this trim datastored by each fuse block can implement eight process trim states. Thesecond register 290 can provide signals for notch tune states. Asillustrated, the second register provides three bits of notch tuningdata. Accordingly, this notch tuning data can implement eight notchtuning states. Tuning data can be generated by adding trim data from afuse block with notch tuning data. By adding the trim data with thenotch tuning data, the tuning data can shift a frequency response of thetunable filter by an offset represented by the trim data. This canimprove performance of the tunable filter. Adding the trim data with thenotch tuning data to generate tuning data can be efficiently implementedwithout more complicated circuitry such as a multiplier. As shown inFIG. 23, the first adder 288 can add 3 bits of trim data from the firstfuse block 286 with 3 bits of notch tuning data from the second register290 to generate 4 bits first tuning data TUNE1. The 4 bits of firsttuning data TUNE1 can set an adjustable impedance circuit of a tunablenotch filter into 16 different states. For instance, each bit of thefirst tuning data TUNE1 can control a switch of the tunable capacitancecircuit of the tunable filter 220 of FIG. 17C.

A trim and control circuit can be implemented in connection with anysuitable number of tunable notch filters. Any of the principles andadvantages discussed herein can be implemented in connection with adevice having two or more tunable notch filters. For instance, trim datacan be provided to two notch filters. As an example, the two notchfilters can be associated with two antennas, such as a primary antennaand a diversity antenna. As shown in FIG. 23, the second adder 289 canadd 3 bits of trim data from the second fuse block 87 with 3 bits ofnotch tuning data from the second register 290 to generate 4 bits secondtuning data TUNE2 for a second tunable notch filter associated with adifferent antenna than the first tuning data TUNE1. Any of theprinciples and advantages discussed herein can be implemented inconnection with a device having two or more antennas. Any of theprinciples and advantages of the trim and control circuits discussedherein can be implemented in connection with any suitable tunablecircuit, such as any of the contour tuning circuits discussed herein.

Any of principles and advantages of the tunable notch filters discussedherein can be implemented in any suitable application that could benefitfrom a tunable notch filter, such as applications in which a tunablenotch filter is in a radio frequency signal path associated with acommon port of a multi-throw switch. For instance, a tunable notchfilter can be arranged to filter out harmonics associated with a radiofrequency signal amplified by a power amplifier. Such a tunable notchfilter can be implemented in a transmit signal path such that thetunable notch filter should not add insertion loss to a receive path.FIGS. 24 and 25 illustrate example radio frequency systems in which atunable notch filter can filter out a harmonic of an amplified radiofrequency signal provided by a power amplifier. Any combination offeatures of the tunable notch filters discussed herein can beimplemented in connection with any suitable principles and advantagesdiscussed with reference to the radio frequency systems of FIGS. 24and/or 25.

FIG. 24 is a schematic diagram of a radio frequency system 292 with atunable notch filter 212 according to an embodiment. As illustrated, theRF system 292 includes a tunable notch filter 212, a trim and controlcircuit 272, a power amplifier 294, a multi-throw switch 296, andfilters 298 a to 298 n. The tunable notch filter 212 of FIG. 24 is inseries in a signal path between the power amplifier 294 and a commonport of the multi-throw switch 296. The power amplifier 294 can be anysuitable power amplifier. For instance, the power amplifier 294 can bearranged to amplify radio frequency signals in a plurality of differentfrequency bands. An amplified RE signal provided by the power amplifier294 can have a harmonic frequency component due to non-linearities of apower amplifier transistor. The power amplifier transistor can be, forexample, a gallium arsenide (GaAs) transistor, a metal oxidesemiconductor (MOS) transistor, or a silicon germanium (SiGe)transistor. Moreover, any of the power amplifiers discussed herein canbe implemented by field effect transistors and/or bipolar transistors,such as heterojunction bipolar transistors.

The trim and control circuit 272 can set the state of the tunable notchfilter 12 to correspond to a frequency band of radio frequency signalbeing amplified by the power amplifier. Accordingly, a harmonicfrequency component such as a second harmonic of an amplified RF signalprovided by the power amplifier 294 can be suppressed by the tunablenotch filter 212. The tunability of the tunable notch filter 212 canenable the harmonic frequency components associated with severalfrequency bands to be selectively filtered out using one filter. Thiscan filter out unwanted harmonics near a source that creates suchunwanted harmonics.

The multi-throw switch 296 can selectively electrically couple theoutput of the power amplifier 294 to a particular filter of theillustrated filters 298 a to 298 n. The multi-throw switch 296 can be ahand select switch and two or more of the filters 298 a to 298 n can beassociated with different frequency bands. The filters 298 a to 298 ncan represent transmit filters of respective duplexers. With the tunablenotch filter 212, the filters 298 a to 298 n can be simplified and/orhave less stringent specifications due to notch filtering in the signalpath from the output of the power amplifier 294 to the common port ofthe multi-throw switch 296. The multi-throw switch 296 can have anysuitable number of throws and a corresponding number of filters 298 a to298 n can be coupled to I/O ports of the multi-throw switch 296.

FIG. 25 is a schematic diagram of a radio frequency system 300 with atunable notch filter 212 according to another embodiment. Asillustrated, the RF system 300 includes a tunable notch filter 212, atrim and control circuit 272, a power amplifier 294, a multi-throwswitch 302 including series switches 303 and 305 and shunt switches 304and 306, a low noise amplifier 307, and a filter 308. The tunable notch212 of FIG. 25 is in a transmit signal path between the power amplifier294 and the filter 308. Accordingly, the tunable notch filter 212 shouldnot add insertion loss to the illustrated receive path. The illustratedmulti-throw switch 302 is a transmit/receive switch that can selectivelyelectrically connect the filter 308 to either a transmit path or areceive path. The filter 308 can be in a signal path between the commonport of the multi-throw switch 302 and an antenna port.

Any of the multi-throw switches discussed herein can include a seriesswitch and a shunt switch for each throw. As shown in FIG. 25, theseries switch 303 and the shunt switch 304 implement a first throw themulti-throw switch 302 and the series switch 305 and the shunt switch306 implement a second throw the multi-throw switch 302. As also shownin FIG. 25, the series switch and the shunt switch for each throw can beimplemented by a field effect transistor. In the illustrated electronicsystem 300, the tunable notch filter can be implemented in a signal pathbetween the series switch 303 of the first throw and the common port ofthe multi-throw switch 302. Accordingly, the tunable notch filter 212 ofFIG. 25 can suppress harmonics from the power amplifier 294 and theseries switch 303.

FIGS. 26A and 26B are schematic diagrams of illustrative packagedmodules. Such packaged modules can include a semiconductor die and oneor more passive components on a packaging substrate enclosed within acommon package. Some such packaged modules can be multi-chip modules.The semiconductor die can be manufactured using any suitable processtechnology. As one example, the semiconductor die can be asemiconductor-on-insulator die, such as a silicon-on-insulator die.

FIG. 26A is a schematic diagram of a packaged module 310 that includes atunable notch filter according to an embodiment. As shown in FIG. 26A,the packaged module 310 can include a semiconductor die 314 and theinductor L_(S) of a tunable notch filter on a packaging substrate 316.The semiconductor die 314 can include a multi-throw switch 312, theseries capacitor C_(S) of the tunable filter, and the tunablecapacitance circuit C_(PT) of the tunable filter. The multi-throw switch312 can be arranged, for example, as an antenna switch or as a bandselect switch. The inductor L_(S) can be implemented as a spiral traceon the packaging substrate 316 or in any other suitable manner toprovide desired characteristics for a tunable notch filter.

FIG. 26B is a schematic diagram of a packaged module 318 that includes atunable notch filter according to an embodiment. The packaged module 318is like the packaged module 310 except that the semiconductor die 319 ofpackaged module 318 includes a trim and control circuit 272.

FIG. 27 is a schematic diagram of an RF system 320 according to anembodiment. The RF system 320 can be referred to as an RF front end. AnRF front end can include circuitry coupled between a baseband processorand an antenna. For instance, an RF front end can include circuitycoupled between a mixer and an antenna. The RF system 320 can includeone or more tunable notch filters in accordance with the any principlesand advantages discussed herein.

As illustrated, the RF system 320 includes power amplifiers 322 and 323,matching networks 324 and 325, RF switches 326 and 327, duplex filters328, receive signal paths 329, an antenna switch 330, antenna filters332 and 333, and antennas 334 and 335, The first power amplifier 322 andthe second power amplifier 323 can be associated with differentfrequency bands and/or different triodes of operation. Each of thesepower amplifiers can amplify RF signals. Matching networks 324 and 325provide impedance matching for outputs of power amplifiers 322 and 323,respectively, to reduce reflections and to improve signal quality.

In certain embodiments, a tunable notch filter can be implemented inconnection with the matching network 324 and/or the matching network325, for example, as described with reference to FIG. 24. The RF switch326 can electrically connect the output of the first power amplifier 322to a selected transmit filter of the duplex filters 328. Similarly, theRF switch 327 can electrically connect the output of the second poweramplifier 323 to a selected transmit filter of the duplex filters 328.The RF switches 326 and/or the RF switch 327 can be multi-throwswitches.

The receive paths 329 can include a low noise amplifier and amulti-throw switch to electrically connect the low noise amplifier to aselected receive filter of the duplex filers 328. A tunable notch filtercan be coupled between a common port of the multi-throw switch of thereceive paths 329 and the low noise amplifier.

An antenna switch 330 can be coupled between the duplex filters 328 andantenna filters 332. The antenna switch 330 can include a multi-throwswitch and control functionality to electrically couple a selectedduplexer in the duplex filters 328 to the antenna 334. The duplexfilters 328 can include a plurality of duplexers. Each of theseduplexers can include a transmit filter and a receive filter. Theantenna filters 332 are coupled between the duplex filters 328 and afirst antenna 334. The antenna 334 can be a primary antenna. The antenna334 can be an antenna of a mobile device, such as a mobile phone.

The antenna filters 332 can filter radio frequency signals propagatingbetween the antenna switch 330 and the antenna 334. The antenna filters332 can include a tunable notch filter. Accordingly, the tunable notchfilter can filter radio frequency signals propagating between theantenna switch 330 and the antenna 334. The antenna filters 332 can alsoinclude another filter, such as a low pass filter, in series with thetunable notch filter in a signal path between the antenna switch 330 andthe antenna 334.

The antenna switch 330 can include a multi-throw multi-pole switch. Inthe RF system 320, the antenna switch 330 includes two poles. The firstpole is associated with the first antenna 334 and the second pole isassociated with the second antenna 336. The antenna filters 333 caninclude a tunable notch filter. The antenna filters 333 can include oneor more features of the antenna filters 332.

FIG. 28A is a schematic block diagram showing more details of antennafilters according to an embodiment. The antenna filters 342 of FIG. 28Aare an example of the antenna filters 332 of FIG. 27. The antennafilters 342 can include a notch filter for providing a zero at a secondharmonic of a carrier and also provide a frequency trap at thirdharmonics of the carrier between the antenna switch module 330 and theantenna 334. The second harmonic zero can be tuned with the tunableimpedance circuit of the tunable notch filter. The antenna filters 342are coupled between the antenna switch module 330 and the antenna 334.As illustrated, the antenna filters 342 include a low pass filter 344and a tunable notch filter 346. The low pass filter 243 of FIG. 18A isan example of the low pass filter 344. The tunable notch filter 346 canimplement any of the principles and advantages of the tunable notchfilters discussed herein. As shown in FIG. 28A, the tunable notch filter346 can be in the signal path between the low pass filter 344 and theantenna 334.

FIG. 28B is a schematic block diagram showing more details of antennafilters according to another embodiment. The antenna filters 348 of FIG.28B are like the antenna filters 344 of FIG. 28A except that the lowpass filter 344 is coupled between the tunable notch filter 346 and theantenna 334. As shown in FIG. 28B, the tunable notch filter 346 can bein the signal path between the antenna switch module 330 and the lowpass filter 344. While FIG. 28A and FIG. 28B illustrate a tunable notchfilter 346 in series with a low pass filter 344, a tunable notch filterin accordance with any of the principles and advantages discussed hereincan be implemented in series with a band pass filter or a high passfilter in some other embodiments.

FIG. 29 is a schematic block diagram of a module 350 according to anembodiment. The illustrated module 350 includes a packaging substrate352 on which a power amplifier 322, a matching network 324, a switch(e.g., a band select switch) 326, duplex filters 328, an antenna switch330, and antenna filters 332 that include a tunable notch filter arearranged. The illustrated elements can be enclosed within a commonpackage. In some other embodiments, the antenna filters 332 can beimplemented in a module and packaged with one or more of the illustratedelements of FIG. 29. Switches of the antenna switch 330 and/or ofembodiments of the tunable notch filter of the antenna filters 332 canbe implemented in semiconductor-on-insulator technology such assilicon-on-insulator technology.

Tunable Notch Filter and Contour Tuning Circuit

A radio frequency system can include a contour tuning circuit and atunable notch filter. Such a radio frequency system can be implementedin accordance with any suitable principles and advantages discussedherein, such as any of the principles and advantages related to tuning ashunt impedance and/or to a tunable notch filter. In certainembodiments, combining features related to contour tuning and a tunablenotch filter can synergistically create an improved radio frequencysystem. For instance, an impedance associated with a selected radiofrequency signal path coupled to a tunable notch filter by way of aradio frequency switch can be matched using a contour tuning circuit.The contour tuning circuit can match different impedances associatedwith different radio frequency signal paths with a consolidated tunablematching network. The tunable notch filter can also be tuned to reject aharmonic of a radio frequency associated with the selected radiofrequency signal path to prevent the harmonic from degrading receiversensitivity. The circuit topology of the tunable notch filter can alsoreduce a large signal amplitude presented to a tunable impedance circuitof the tunable notch filter.

FIGS. 30, 31, and 32 illustrate example radio frequency systems thatinclude a contour tuning circuit and a tunable notch filter. The contourtuning circuit and tunable notch filter in each of these systems arecoupled in a signal path between a common port of a multi-throw switchand either an antenna or a radio frequency circuit. The contour tuningcircuit and/or the tunable notch filter can be tuned based on whichradio signal path the multi-throw switch couples to the contour tuningcircuit and the tunable notch filter. Accordingly, the contour tuningcircuit can provide impedance matching for a selected radio frequencysignal path and the tunable notch filter can be adjusted to reject afrequency corresponding to the selected radio frequency signal path.

FIG. 30 is a schematic diagram of a radio frequency system 360 accordingto an embodiment. As illustrated, the radio system 360 includes acontour tuning circuit 12, a tunable notch filter 212, an antenna switch364, a control circuit 368, and an antenna 369 arranged to transmit andreceive radio frequency signals.

The antenna switch 364 can be implemented in accordance with anysuitable principles and advantages discussed herein in connection withmulti-throw switches. As illustrated, antenna switch 364 has multiplethrows. The antenna switch 364 can have any suitable number of throws,such as least 8 throws in certain embodiments. The antenna switch 364 isillustrated as having a single pole and a single common port. In someother embodiments, the antenna switch 364 can have two or more poles.

The contour tuning circuit 12 can be implemented in accordance with anysuitable principles and advantages discussed herein in connection withtunable circuits. The illustrated contour tuning circuit 12 is a tunablecircuit configured to adjust an effective shunt impedance in a signalpath from the antenna switch 364 to the antenna 369 in association witha state of the antenna switch 364 changing. For instance, the contourtuning circuit 12 can adjust the effective shunt impedance before,during, or after the state of the antenna switch 364 changes. This canadjust the effective shunt impedance for providing different impedancematching for different respective states of the antenna switch 364. Asillustrated, the tunable circuit includes a shunt inductor L₁ inparallel with a tunable capacitance circuit C_(T).

The tunable note filter 212 can be implemented in accordance with anysuitable principles and advantages discussed herein in connection withtunable notch filters. The tunable notch filter 212 is coupled in seriesbetween the antenna switch 364 and the antenna 369. The tunable notchfilter 212 is configured to filter a radio frequency signal propagatingbetween the antenna switch 364 and the antenna 369. For instance, theradio frequency signal can propagate from the antenna switch 364 to theantenna 369 to transmit the radio frequency signal from the antenna 369.As another example, the radio frequency signal can propagate from theantenna 369 to antenna switch 364 to the facilitate processing a signalreceived from the antenna 369. The tunable notch filter 212 can be tunedso as to have a frequency response with a notch at a second harmonicfrequency of a radio frequency signal propagating between the antennaswitch 364 and the antenna 369. As illustrated, the tunable notch filter212 includes a series LC circuit in parallel with a a tunablecapacitance circuit C_(PT). The series LC circuit can be inductive atfrequencies above a resonant frequency of the series LC circuit so as tocreate a parallel resonance with the tunable capacitance circuit C_(PT).

The control circuit 368 can control the tunable capacitance circuitC_(PT) such that an effective capacitance in parallel with the series LCcircuit of the tunable notch filter 212 corresponds to a frequency ofthe radio frequency signal propagating between the radio frequencyswitch 364 and the antenna 369.

The control circuit 368 can the tunable capacitance circuit C_(T) of thecontour tuning circuit 12 on as to provide a first effective shuntimpedance when a first throw of the antenna switch 364 is active and toprovide a second effective impedance when a second throw of the antennaswitch 364 is active. This can provide impedance matching tailored to aselected radio frequency signal path being coupled to the common port ofthe antenna switch 364. For instance, the control circuit 368 can set astate of the tunable capacitance circuit C_(T) based on an impedanceassociated with a trace arranged to route from a duplexer to a throw ofthe antenna switch 364 that is activated.

In some embodiments, a trim and control circuit including non-volatilememory storing trim data can set a state of the tunable capacitancecircuit C_(T) of the contour tuning circuit 12 and/or the tunablecapacitance circuit C_(PT) the tunable notch filter 212. Such a trim andcontrol circuit can implement any suitable combination of features ofthe trim and control circuits discussed herein.

FIG. 31 is a schematic diagram of a radio frequency system 370 thatincludes a tunable notch filter 212 and a contour tuning circuit 12according to another embodiment. The radio frequency system 370 is likethe radio frequency system 360 of FIG. 30 except that the radiofrequency system 370 includes another filter 376 in a signal pathbetween the antenna switch 364 and the antenna 369. The filter 376 canbe any suitable filter. The filter 376 can be a low pass filter, abandpass filter, or a high pass filter. In certain embodiments, thefilter 376 can be implemented in accordance with any of the principlesand advantages of the filter 46 of FIG. 5 and/or the 243 filter of FIG.18A. As illustrated, the filter 376 can be coupled in a signal pathbetween the contour tuning circuit 12 and the tunable notch filter 376in certain embodiments.

FIG. 32 is a schematic diagram of a radio frequency system 380 thatincludes a tunable notch filter 212 and a contour tuning circuit 12according to another embodiment. The radio frequency system 380 is likethe radio frequency system 360 of FIG. 30 except that the radiofrequency system 380 includes (1) RF signal paths 383 a to 383 n coupledto a multi-throw switch 386 and (2) a radio frequency circuit 386 inplace of the antenna 369 of FIG. 30. FIG. 32 illustrates that a contourtuning circuit can be implemented with a tunable notch filter in adifferent context that between an antenna switch and an antenna port.The RF signal paths 383 a to 383 n can be any suitable RF signal paths.For instance, the RF signal paths 383 a to 383 can each include aduplexer and a signal route coupled to a port of the multi-throw switch364. The radio frequency circuit 386 can be any suitable radio frequencycircuit configured to process a radio frequency signal. As one example,the radio frequency circuit 386 can include a power amplifier 386configured to provide an amplified radio frequency signal to themulti-throw switch 384.

According to some other embodiments, a tunable notch filter can beimplemented in a transmit path and a contour tuning circuit can beimplemented in a receive path. For instance, a tunable notch filter canbe coupled between an output of a power amplifier and a duplexer (forexample, as show in FIG. 24 or FIG. 25) and a contour tuning circuit canbe coupled between a multi-throw receive switch and a low noiseamplifier (for example, as shown in FIG. 11B).

FIGS. 33 and 34 illustrate example packaged modules that include acontour tuning circuit and a tunable notch filter. The contour tuningcircuit and the tunable notch filter can be implemented with anysuitable principles and advantages discussed herein. These packagedmodules include a semiconductor die and passive components on apackaging substrate enclosed within a common package. Some such packagedmodules can be multi-chip modules. The semiconductor die can bemanufactured using any suitable process technology. As one example, thesemiconductor die can be a semiconductor-on-insulator die, such as asilicon-on-insulator die.

A packaged module can include a multi-throw switch configured toelectrically connect a selected one of its input/output ports to acommon port, a tunable circuit configured to adjust an effective shuntimpedance coupled to the common port in association with a state of themulti-throw switch changing, and a tunable notch filter coupled inseries in a radio frequency signal path associated with the common port.The multi-throw switch, the tunable circuit, and the tunable notchfilter being can be included within a common package. Some such packagedmodules can also include a power amplifier within the common package.

FIG. 33 is a schematic diagram of a packaged module 390 that includes atunable notch filter and a contour tuning circuit according to anembodiment. As shown in FIG. 33, the packaged module 390 can include asemiconductor die 392, an inductor L₁ of a contour tuning circuit, andan inductor L_(S) of a tunable notch filter on a packaging substrate394. The semiconductor die 392 can include a multi-throw switch 394, theseries capacitor C_(S) of the tunable filter, and the tunablecapacitance circuit C_(PT) of the tunable notch filter. The multi-throwswitch 394 can be arranged, for example, as an antenna switch. Theillustrated inductor L_(S) and/or L₁ can be implemented as a spiraltrace on the packaging substrate 394 or/or in any other suitable mannerto provide desired characteristics for such inductors.

FIG. 34 is a schematic diagram of a packaged module 395 that includes atunable notch filter and a contour tuning circuit according to anotherembodiment. The packaged module 390 is like the packaged module 390 ofFIG. 34 except that the semiconductor die 392 of packaged module 395includes a trim and control circuit 396. The trim and control circuit396 can include memory, such as non-volatile memory, arranged to storetrim data. The trim and control circuit 396 can set a state of thetunable notch filter and/or on the contour tuning circuit based on thetrim data.

Wireless Communication Device

FIG. 35 is a schematic block diagram of illustrative wirelesscommunication device 400 that includes a tunable notch filter and/or acontour tuning circuit in accordance with one or more embodiments. Thewireless communication device 400 can be any suitable wirelesscommunication device. For instance, a wireless communication device 400can be a mobile phone, such as a smart phone. As illustrated, thewireless communication device 400 includes an antenna 401, an RF frontend 402, an RF transceiver 403, a processor 404, and a memory 405. Theantenna 401 can transmit RF signals provided by the RF front end 402.The antenna 401 can provided received RF signals to the RF front end 402for processing.

The RF front end 402 can include one or more power amplifiers, one ormore low noise amplifiers, RF switches, receive filters, transmitfilters, duplex filters, or any combination thereof. The RF front end402 can be configured to transmit and receive RF signals associated withany suitable communication standards.

Any of the tunable notch filters discussed herein can be implemented inthe RF front end 402. For instance, a tunable notch filter can beincluded in antenna filters of the RF front end 402 in a signal pathbetween an antenna switch and the antenna 401. Alternatively oradditionally, a tunable notch filter can be in a signal path between apower amplifier of the RF front end 402 and an RF switch of the RF frontend 402.

Any of the contour tuning circuits discussed herein can be implementedin the RF front end 402. For instance, a contour tuning circuit can beincluded in antenna filters of the RF front end 402 in a signal pathbetween an antenna switch and the antenna 401. Alternatively oradditionally, a contour tuning circuit can be in a signal path between acommon port of a multi-throw receive switch of the RF front end 402 anda low noise amplifier of the RF front end 407.

According to certain embodiments, the RF front end 402 includes atunable notch filter and a contour tuning circuit. As an example, acontour tuning circuit and a tunable notch filter can be included inantenna filters of the RF front end 402 in a signal path between anantenna switch and the antenna 401.

The RF transceiver 403 can provide RF signals to the RF front end 40 foramplification and/or other processing. The RF transceiver 403 can alsoprocess an RF provided by a low noise amplifier of the RF front end 402.The RF transceiver 403 is in communication with the processor 404. Theprocessor 404 can be a baseband processor. The processor 404 can provideany suitable base band processing functions for the wirelesscommunication device 400. The memory 405 can be accessed by theprocessor 404. The memory 405 can store any suitable data for thewireless communication device 400.

Applications

Any of the principles and advantages discussed herein can be applied toother systems, not just to the systems described above. The elements andoperations of the various embodiments described above can be combined toprovide further embodiments. Some of the embodiments described abovehave provided examples in connection with antenna filters, RF modulesand/or wireless communications devices. However, the principles andadvantages of the embodiments can be used in connection with any othersystems, apparatus, or methods that benefit could from any of theteachings herein. For instance, any suitable principles and advantagesdiscussed herein can be implemented in an electronic system that coupledbenefit from a contour tuning circuit and/or a shunt inductor inparallel with a tunable capacitance circuit. As another example, anysuitable principles and advantages discussed herein can be implementedin an electronic system that could benefit from a tunable notch filterhave one or more features discussed herein. Any of the principles andadvantages discussed herein can be implemented in RF circuits configuredto process radio frequency signals in a range from about 30 kHz to 300GHz, such as in a range from about 450 MHz to 6 GHz.

Aspects of this disclosure can be implemented in various electronicdevices. Examples of the electronic devices can include, but are notlimited to, consumer electronic products, parts of the consumerelectronic products such as semiconductor die and/or a packaged radiofrequency module, electronic test equipment, cellular communicationsinfrastructure such as a base station, etc. Examples of the electronicdevices can include, but are not limited to, a mobile phone such as asmart phone, a wearable computing device such as a smart watch or an earpiece, a telephone, a television, a computer monitor, a computer, amodem, a hand-held computer, a laptop computer, a tablet computer, anelectronic book reader, a personal digital assistant (PDA), a microwave,a refrigerator, a stereo system, a DVD player, a CD player, a digitalmusic player such as an MP3 player, a radio, a camcorder, a camera, adigital camera, a portable memory chip, a health care monitoring device,a vehicular electronics system such as an automotive electronics systemor an avionics electronic system, a washer, a dryer, a washer/dryer, aperipheral device, a wrist watch, a clock, etc. Further, the electronicdevices can include unfinished products.

CONCLUSION

Unless the context requires otherwise, throughout the description andthe claims, the words “comprise,” “comprising,” “include,” “including,”and the like are to be construed in an inclusive sense, as opposed to anexclusive or exhaustive sense; that is to say, in the sense of“including, but not limited to.” The words “electrically coupled”, asgenerally used herein, refer to two or more elements that may be eitherdirectly electrically coupled, or electrically coupled by way of one ormore intermediate elements. Likewise, the word “connected”, as generallyused herein, refers to two or more elements that may be either directlyconnected, or connected by way of one or more intermediate elements. Aradio frequency signal can have a frequency in the range from 300 MHz to300 GHz, such as in a range from about 450 MHz to about 6 GHz.Additionally, where appropriate, the words “herein,” “above,” “below,”and words of similar import, when used in this application, shall referto this application as a whole and not to any particular portions ofthis application. Where the context permits, words in the above DetailedDescription of Certain Embodiments using the singular or plural numbermay also include the plural or singular number, respectively. The word“or” in reference to a list of two or more items, where context permits,covers all of the following interpretations of the word: any of theitems in the list, all of the items in the list, and any combination ofthe items in the list. The term “based on,” as generally used herein,encompasses the following interpretations of the term: solely based on,or based at least partly on.

Moreover conditional language used herein, such as, among others, “can,”“could,” “might,” “may,” “e.g.,” “for example,” “such as” and the like,unless specifically stated otherwise, or otherwise understood within thecontext as used, is generally intended to convey that certainembodiments include, while other embodiments do not include, certainfeatures, elements and/or states. Thus, such conditional language is notgenerally intended to imply that features, elements and/or states are inany way required for one or more embodiments or that one or moreembodiments necessarily include logic for deciding, with or withoutauthor input or prompting, whether these features, elements and/orstates are included or are to be performed in any particular embodiment.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of the disclosure. Indeed, the novel apparatus, methods, andsystems described herein may be embodied in a variety of other forms.Furthermore, various omissions, substitutions and changes in the form ofthe methods and systems described herein may be made without departingfrom the spirit of the disclosure. For example, while blocks arepresented in a given arrangement, alternative embodiments may performsimilar functionalities with different components and/or circuittopologies, and some blocks may be deleted, moved, added, subdivided,combined, and/or modified. Each of these blocks may be implemented in avariety of different ways. For example, circuit blocks described hereinmay be deleted, moved, added, subdivided, combined, and/or modified.Each of these circuit blocks may be implemented in a variety ofdifferent ways. Any of the circuits disclosed herein can be implementedby logically and/or functionally equivalent circuits. Any suitablecombination of the elements and acts of the various embodimentsdescribed above can be combined to provide further embodiments.

What is claimed is:
 1. A radio frequency circuit comprising: an antennaswitch having multiple throws; a tunable circuit configured to adjust aneffective shunt impedance in a signal path from the antenna switch to anantenna port in association with a state of the antenna switch changing;a tunable notch filter coupled in series between the antenna switch andthe antenna port, the tunable notch filter being configured to filter aradio frequency signal propagating between the antenna switch and theantenna port; and a control circuit configured to set a state of thetunable circuit based on an impedance associated with a trace arrangedto route from a duplexer to a throw of the antenna switch that isactivated.
 2. The radio frequency circuit of claim 1 wherein the tunablenotch filter includes a series LC circuit in parallel with a tunablecapacitance circuit.
 3. The radio frequency circuit of claim 2 whereinthe series LC circuit is inductive at frequencies above a resonantfrequency of the series LC circuit so as to create a parallel resonancewith the tunable capacitance circuit.
 4. The radio frequency circuit ofclaim 2 wherein the control circuit is further configured to control thetunable capacitance circuit such that an effective capacitance inparallel with the series LC circuit corresponds to a frequency of theradio frequency signal.
 5. The radio frequency circuit of claim 2wherein the tunable capacitance circuit and the antenna switch areintegrated on a common semiconductor die.
 6. The radio frequency circuitof claim 1 wherein the tunable notch filter is arranged to have afrequency response with a notch at a second harmonic frequency of theradio frequency signal.
 7. The radio frequency circuit of claim 1wherein the tunable circuit includes a shunt inductor in parallel with atunable capacitance circuit.
 8. The radio frequency circuit of claim 1wherein the control circuit is configured to control the tunable circuitso as to provide a first effective shunt impedance when a first throw ofthe antenna switch is active and to provide a second effective impedancewhen a second throw of the antenna switch is active.
 9. The radiofrequency circuit of claim 1 wherein the antenna switch has at least 8throws.
 10. The radio frequency circuit of claim 1 further comprising atrim and control circuit including non-volatile memory storing trimdata, the trim and control circuit configured to set a state of thetunable notch filter based on the trim data.
 11. A packaged modulecomprising: a multi-throw switch including input/output ports and acommon port, the multi-throw switch configured to electrically connect aselected one of the input/output ports to the common port; a tunablecircuit configured to adjust an effective shunt impedance coupled to thecommon port in association with a state of the multi-throw switchchanging; a control circuit configured to set a state of the tunablecircuit based on an impedance associated with a trace coupled to aselected throw of the multi-throw switch; and a tunable notch filtercoupled in series in a radio frequency signal path associated with thecommon port; the multi-throw switch, the tunable circuit, the controlcircuit, and the tunable notch filter being included within a commonpackage.
 12. The packaged module of claim 11 wherein the tunable circuitincludes a shunt inductor in parallel with a tunable capacitancecircuit.
 13. The packaged module of claim 11 wherein the tunable notchfilter includes a series LC circuit in parallel with a tunablecapacitance circuit.
 14. The packaged module of claim 11 wherein thetunable notch filter is configured to provide rejection at a secondharmonic of a radio frequency signal propagating between the common portand the tunable notch filter.
 15. The packaged module of claim 11further comprising a trim and control circuit including memory arrangedto store trim data, the trim and control circuit configured to set astate of the tunable notch filter based on the trim data.
 16. Thepackaged module of claim 11 further comprising a power amplifierincluded within the common package.
 17. A wireless communication devicecomprising: an antenna configured to receive a radio frequency signal;an antenna switch configured to electrically couple a first radiofrequency signal path to the antenna in a first state and toelectrically couple a second radio frequency signal path to the antennain a second state; a tunable circuit configured to adjust an effectiveshunt impedance in a signal path from the antenna switch to the antennain association with a state of the antenna switch changing; a controlcircuit configured to control the tunable circuit such that theeffective shunt impedance is based on an impedance of the first radiofrequency signal path between a duplexer and the antenna switch when theantenna switch is in the first state; and a tunable notch filter coupledin series between the antenna switch and the antenna.
 18. The wirelesscommunication device of claim 17 wherein the tunable circuit isconfigurable into at least 8 states.
 19. The wireless communicationdevice of claim 17 configured as a mobile phone.
 20. The wirelesscommunication device of claim 17 further comprising duplexers coupled tothe antenna switch by respective traces, the duplexers including theduplexer.